Name: a small volume procedure for viral concentration from water
Uploaded: 2015-02-03T13:00:00.000+00:00
Duration: 7 min 28 s
Description: Watch this Scientific Journal Video about A Small Volume Procedure for Viral Concentration from Water at JoVE.com

<p class='jove_content'>We would like to thank Dr. Nicholas J. Ashbolt and Dr. G. Shay Fout for their review of the manuscript.</p>

<p class="jove_title"> 유리 및 필터 하우징 1. 준비 </p><ol style="margin-left: 40px;"><li> 특별히 언급하지 않는 한, 15 분 동안 121 ° C에서 모든 유리, 필터 하우징 및 솔루션을 소독. 불임을 보장하기 위해 모든 개구 또는 알루미늄 호일 또는 이전 살균에 테이프 확보 종이 중 하나에 노출 된 표면을 커버합니다. </li><li> 1 L 사이드 암 삼각 플라스크에 필터 하우징 (47mm 직경)를 부착하여 여과 장치를 조립합니다. 필요한 필터를 수집 : 47mm 직경 전기 음성 / 전기 양성 디스크 필터를. </li><li> 1 L의 1.5 %의 쇠고기 추출물 준비 (응집을 플록 입자를 생성 용액의 pH를 3.5, 또는 비 응집 저하되면, pH를 3.5에서 골재를하지 않는) 비프 엑기스 15g에 용해시켜, 0.05 M 글리신, 1 탈 이온수의 L과 3.75 g 글리신을 추가. <br /> 주 : 비 응집 쇠고기 추출물 전에 급 농도 셀 라이트의 첨가를 필요로 할 것이다. </li><li> 용출 첨가제 나트륨 polyph 추가0.1 % 농도에서 쇠고기 추출물 osphate. </li><li> 1 M 염산 용액을 첨가 쇠고기 추출물, 원하는 산도로 pH를 혼합 용액에 적가 하였다. 121 ℃에서 15 ~ 30 분간 오토 클레이브 쇠고기 추출물. </li><li> 잘, 매체, 또는 (비 응집 쇠고기 추출물 만 함께 사용) 큰 입자 셀 라이트 0.1 g을 측정합니다. </li><li> 삼각 부착 플라스크에 진공 출구에 대응 튜브를 부착함으로써 진공 / 흡착을 준비한다. </li></ol><p class="jove_title"> 솔루션 및 바이러스 재고 2. 준비 </p><ol style="margin-left: 40px;"><li> 1 M HCl을 1 L를 준비합니다. </li><li> 1 M NaOH를 1 L를 준비합니다. </li><li> 1X PBS 용액을 준비합니다 (137 mM의 NaCl을, 2.7 mM의 KCl을, 1.47 mM의 K <sub>2</sub> PO <sub>4,</sub> 4.3 mM의의 NaH <sub>2</sub> PO <sub>4).</sub> <ol><li> 1 M의 NaOH를 사용하여 9.0 1X PBS의 산도를 조정합니다. </li></ol></li><li> 준비하고 9 ㎖의 PBS (PH와 재고 바이러스 1 ㎖를 혼합하여 10 <sup>4</sup> -10 <sup>5</sup> 가장 가능성있는 수 (MPN) ml의 <sup>-1</sup> 스톡 바이러스를 희석7), <sup>8, 13을</sup> 앞서 기재된. 1 ml의 분취 량에서 -80 ° C에서 보관. <ol><li> 잠재적 오염물을 제거하기 위해 필터링 주사기 (0.22 ㎛의 공극 크기)에 의해 바이러스 스톡 멸균. </li></ol></li><li> 탈 염소 수돗물 <ol><li> 측정 값을 이용하여 무균 살균 수돗물 1 L 눈금 실린더 및 자기 교반 막대를 함유하는 2 L 비이커에 붓는다. </li><li> 티오 황산나트륨 0.7 g을 추가하고 입자가 용해 될 때까지 섞는다. 1 M 염산 또는 1 M NaOH 용액을 사용하여 필요한 경우 7-7.5에 수돗물의 산도를 조정합니다. </li><li> 해동 바이러스 스파이크 (1 mL) 및 탈 염소 살균 수돗물 1 L로 스파이크의 전체 볼륨. 10 분 동안 혼합한다. </li><li> 스파이크 된 샘플과 동일한 방법으로 각각의 실험 과정에있어서 블랭크 (아데노 않고 탈 염소 수돗물)을 준비한다. </li></ol></li></ol><p class="jove_title"> 밀리 포어 필터 장치의 제조 3 </p><ol style="margin-left: 40px;"><li> 필터 하우징을 통해 멸균 덮개를 제거합니다. 확인필터 하우징 상부 그릇과 낮은 필터 스크린 사이의 적절한 맞춤 여과시 시료 누출을 방지 할 수 있습니다. </li><li> 1 L 삼각 플라스크에서 멸균 덮개를 제거합니다. 좋은 도장을 만들어, 필터 유닛의 코르크 삼각 플라스크의 상단 구멍에 꼭 맞는지 확인합니다. </li><li> 낮은 필터 화면에서 필터 유닛 위에 그릇을 제거하고 멸균 집게로 화면을 통해 정면으로 47mm 전기 양성 필터 디스크를 넣습니다. 화면 하단에 필터 하우징 그릇을 부착하고 시계 반대 방향으로 비틀 어서 제자리에 고정. </li></ol><p class="jove_title"> 4. 물 여과 (기본 농도) </p><ol style="margin-left: 40px;"><li> 바이러스 100 ml의 멸균 졸업 된 실린더 사용하여 수돗물 아군 측정한다. </li><li> 바이러스 100ml를 47mm 플리츠 유리 / 셀룰로오스 필터 또는 나노 알루미나 / 유리 섬유 디스크 필터를 포함하는 필터 하우징 내로 수돗물 아군 붓는다. </li><li> 물이 천천히 필터를 통과하도록 허용합니다. 오 남아있는 잔여 물을 제거하기 위해 부드러운 진공 적용필터 표면에서 F 수돗물. </li><li> 트립신 처리를 사용하는 경우, 표면을 필터링하고 5 분 동안 배양 0.25 % 트립신 5 ㎖를 추가합니다. </li><li> 멸균 탈 50 ml의 물을 사용하여 필터 표면에서 트립신을 씻으십시오. </li></ol><p class="jove_title"> 필터 5. 바이러스 용출 </p><ol style="margin-left: 40px;"><li> 2 L 삼각 플라스크에서 필터 하우징을 제거하고, 250 ml의 사이드 암 플라스크에 배치합니다. </li><li> 눈금 실린더를 사용 하 쇠고기 추출물 100 ㎖를 측정한다. 천천히 필터 하우징에 쇠고기 추출물 100 ㎖를 붓는다. </li><li> 쇠고기 추출물은 작은 (250 ml)을 삼각 플라스크에 쇠고기 추출물을 캡처, 필터를 통해 붓는다. 필터에서 잔류 쇠고기 추출물을 뽑아 진공을 적용합니다. </li></ol><p class="jove_title"> 6. 셀 라이트 보조 농도 </p><ol style="margin-left: 40px;"><li> 볶음 판에 용출 된 바이러스를 포함하는 전송 플라스크. 약간의 소용돌이를 만들 혼합, 교반 접시에 무균 자기 교반 막대와 장소를 추가합니다. </li><li> 셀 라이트 0.1 g을 넣고쇠고기 추출물 100 ㎖에 분말과 셀 라이트를 분산 할 수 있습니다. 쇠고기 추출물로 멸균 산도 프로브를 놓습니다. </li><li> pH가 4.0을 달성하기 위해 쇠고기 추출물에 현명한 1 M 염산을 떨어 추가합니다. 천천히 10 분 동안 혼합 할 수 있습니다. </li><li> 2 L 삼각 플라스크를 사용하여 (전술 한 바와 같이) 필터 하우징 상에 47mm 프리 필터를 놓습니다. </li><li> 프리 필터를 통해 100 ml의 쇠고기 추출물 / 셀 라이트 혼합물을 붓고. 쇠고기 추출물을 통해 붓는다. 필터에서 잔류 쇠고기 추출물을 뽑아 약간의 진공을 적용합니다. </li><li> 필터 하우징 배출구의 끝에 금속 튜브 클립을 놓습니다. 금속 튜브 클립에 멸균 15 ml의 폴리 프로필렌 수집 튜브를 연결합니다. 다시 삼각 플라스크에 넣고 필터 하우징을 놓습니다. </li><li> 프리 필터에 포집 셀 라이트를 통해 1X PBS 버퍼 5 ㎖, pH가 9.0를 추가합니다. </li><li> PBS는 프리 필터를 통해 물방울을 허용합니다. 15 ml의 수집 관에 잔류 PBS를 통해 당기하려면 약간의 진공을 적용합니다. </li></ol><p class="jove_title"> 7. 유기 응집 보조 농도 </p><ol style="margin-left: 40px;"><li>볶음 판에 용출 된 바이러스가 들어있는 비커를 전송합니다. 쇠고기 추출물을 100 ml의 멸균 자기 교반 막대를 추가하고 약간의 소용돌이를 만들 섞는다. </li><li> 쇠고기 추출물로 멸균 산도 프로브를 놓습니다. </li><li> 쇠고기 추출물 현명한 1 M 염산 드롭을 추가하고 3.5로 산도를 조정합니다. 30 분 동안 혼합한다. </li><li> 4 ºC에서 15 분 동안 2,500 XG에 250 ml의 원심 분리기 원뿔 튜브에 용출액을 원심 분리기를 따르십시오. </li><li> 펠렛을 방해하지 않도록 상층 액을 복용 치료를 붓고. 1X PBS, pH가 9 5ml에 펠렛을 재현 탁. </li><li> 4 ºC에서 10 분 동안 4,000 XG에 현탁액을 원심 분리기. 상층 액을 붓고 펠렛을 폐기합니다. </li><li> 7-7.5로 pH를 조정, 필터는 -80 ° C에서 0.22 μm의 주사기 필터 및 동결을 통해 소독. </li></ol><p class="jove_title"> 8. 바이러스 핵산 추출 </p><ol style="margin-left: 40px;"><li> 제조업체의 지침에 따라 적절한 상용 키트를 사용하여 바이러스 핵산을 추출합니다. </li></ol> &lt;P 클래스 = &quot;jove_title&quot;&gt; 9. ADV 40/41 qPCR에 </p><ol style="margin-left: 40px;"><li> <sup>8, 13을</sup> 발표 한 프라이머 및 프로브뿐만 아니라, 반응 혼합물과 열 순환 프로파일을 사용합니다. <br /> 주 : 분석의 검출의 예상 한계 반응 당 약 5 qPCR의 단위입니다. </li><li> 다음과 같은 농도에서 PCR 증폭 혼합물의 구성 요소를 추가 : 10 mM 트리스 (PH 8.3)의 50 mM의 KCl을, 4.5 mM의의 MgCl <sub>2,</sub> 10 mM의 dNTPs를, 10 μM 프라이머 1 μm의 프로브와 중합 효소 0.5 μL 그래서 45의 최종 볼륨 μL를 96- 웰 PCR 반응 플레이트 내에 웰의 적절한 수에 첨가 될 수있다. </li><li> 96 웰, 빠른 반응 PCR 플레이트의 각 해당 잘으로 PCR 증폭 혼합물의 부하 45 μL. </li><li> DNA의 5 μL는 PCR 플레이트의 적절한 우물에 샘플을 추출 추가합니다. </li><li> , 내열성 커버 씰 플레이트를 커버 PCR 판 우물의 바닥에있는 방울을 이동 판을 회전. </li><li> foll으로 설정 PCR 증폭주기OWS : 15 초 동안 95 ° C의 40주기와 1 분 60 ° C 다음에 10 분 동안 95 ° C. </li></ol><p class="jove_title"> 10. 데이터 분석 </p><ol style="margin-left: 40px;"><li> 5에서 1 : 1의 샘플에 걸친 일련의 5 배 희석액 중으로 측정 분석 (625)의 희석 범위를 바이러스 입자의 가장 가능한 번호 (MPN)을 결정하기 위해, <sup>8, 13을</sup> 앞서 설명 된 바와 같이. </li><li> 5에서 1 : 1 아데노 바이러스 실험을 걸친 일련의 스파이크 5 배 희석액을 분석 15,625 희석 범위를 바이러스 입자의 가장 가능한 번호 (MPN)을 결정하기 위해. </li><li> EPA MPN 계산기 (http://www.epa.gov/nerlcwww/online.html)를 사용하여, 희석의 유형을 고려하여 조정 계산기 (1 : 5 1:10), 희석 수 행하고, 숫자 일련의 희석에 샘플을 복제. </li><li> 수행 볼륨 단위로 <em>등 (예를 들면,</em> 1 ㎖, 100 ㎖를 정규화하여 다음 데이터의 <sub>열</sub> 변형 로그 </EM&gt;). 샘플에 존재하는 바이러스 입자의 수​​를 나누어 주어 실험에 대한 회수율을 계산 실험 스파이크에 존재하는 바이러스 입자의 수​​에 집중하고 있습니다. </li><li> 다른 실험 변수의 효과를 평가 <em>(예를 들어,</em> 다른 셀 라이트 타입의 pH 범위에서, 다른 필터 타입과 상이한 이차 농도 기법) <em>(예를 들면,</em> 짝 t 검정, 하나 또는 두 개의 파라 메트릭 또는 비 - 파라 메트릭 통계 테스트를 수행하여 ADV 회수율에 데이터의 분배 및 실험 디자인에 따라)을 - 방향 ANOVA. </li></ol>

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R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>ICR microbial laboratory manual</em>. <b>178</b>, (1996).</li><li>Calgua, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+application+of+a+one-step+low+cost+procedure+to+concentrate+viruses+from+seawater+samples.">Development and application of a one-step low cost procedure to concentrate viruses from seawater samples.</a> <em style='font-style: italic'>Journal of Virological Methods</em>. <b>153</b>, 79-83 (2008).</li><li>Calgua, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+and+quantification+of+classic+and+emerging+viruses+by+skimmed-milk+flocculation+and+PCR+in+river+water+from+two+geographical+areas.">Detection and quantification of classic and emerging viruses by skimmed-milk flocculation and PCR in river water from two geographical areas.</a> <em style='font-style: italic'>Water Research</em>. <b>47</b>, 2797-2810 (2013).</li><li>McMinn, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+adenovirus+40+and+41+recovery+from+tap+water+using+small+disk+filters.">Optimization of adenovirus 40 and 41 recovery from tap water using small disk filters.</a> <em style='font-style: italic'>Journal of Virological Methods</em>. <b>193</b> (2), 284-290 (2013).</li><li>Brinkman, N. E., Haffler, T. D., Cashdollar, J. L., Rhodes, E. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+methods+using+celite+to+concentrate+norovirus,+adenovirus+and+enterovirus+from+wastewater.">Evaluation of methods using celite to concentrate norovirus, adenovirus and enterovirus from wastewater.</a> <em style='font-style: italic'>Journal of Virological Methods</em>. <b>193</b>, 140-146 (2013).</li><li>Albinsson, B., Kidd, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenovirus+type+41+lacks+an+RGD+alpha(v)-integrin+binding+motif+on+the+penton+base+and+undergoes+delayed+uptake+in+A549+cells.">Adenovirus type 41 lacks an RGD alpha(v)-integrin binding motif on the penton base and undergoes delayed uptake in A549 cells.</a> <em style='font-style: italic'>Virus Research</em>. <b>64</b>, 125-136 (1999).</li><li>He, C., Lian, J. S., Jiang, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electronic+structures+and+hydrogen+bond+network+of+high-density+and+very+high-density+amorphous+ices.">Electronic structures and hydrogen bond network of high-density and very high-density amorphous ices.</a> <em style='font-style: italic'>The Journal of Physical Chemistry. B</em>. <b>109</b>, 19893-19896 (2005).</li><li>Sedmak, G., Bina, D., Macdonald, J., Couillard, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nine-year+study+of+the+occurrence+of+culturable+viruses+in+source+water+for+two+drinking+water+treatment+plants+and+the+influent+and+effluent+of+a+Wastewater+Treatment+Plant+in+Milwaukee,+Wisconsin.">Nine-year study of the occurrence of culturable viruses in source water for two drinking water treatment plants and the influent and effluent of a Wastewater Treatment Plant in Milwaukee, Wisconsin.</a> <b>71</b>, 1042-1050 (2005).</li><li>Soto-Beltran, M., Ikner, L. A., Bright, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effectiveness+of+poliovirus+concentration+and+recovery+from+treated+wastewater+by+two+electropositive+filter+methods.">Effectiveness of poliovirus concentration and recovery from treated wastewater by two electropositive filter methods.</a> <em style='font-style: italic'>Food and Environmental Virology</em>. <b>5</b>, 91-96 (2013).</li><li>Haramoto, E., Katayama, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+acidic+elution+to+virus+concentration+using+electropositive+filters.">Application of acidic elution to virus concentration using electropositive filters.</a> <em style='font-style: italic'>Food and Environmental Virology</em>. <b>5</b>, 77-80 (2013).</li><li>Lee, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+electropositive+filtration+for+recovering+norovirus+in+water.">Evaluation of electropositive filtration for recovering norovirus in water.</a> <em style='font-style: italic'>Journal of Water and Health</em>. <b>9</b>, 27-36 (2011).</li><li>Gibbons, C. D., Rodriguez, R. A., Tallon, L., Sobsey, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+positively+charged+alumina+nanofibre+cartridge+filters+for+the+primary+concentration+of+noroviruses,+adenoviruses+and+male-specific+coliphages+from+seawater.">Evaluation of positively charged alumina nanofibre cartridge filters for the primary concentration of noroviruses, adenoviruses and male-specific coliphages from seawater.</a> <em style='font-style: italic'>Journal of Applied Microbiology</em>. <b>109</b>, 635-641 (2010).</li><li>Hill, V. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+rapid+method+for+simultaneous+recovery+of+diverse+microbes+in+drinking+water+by+ultrafiltration+with+sodium+polyphosphate+and+surfactants.">Development of a rapid method for simultaneous recovery of diverse microbes in drinking water by ultrafiltration with sodium polyphosphate and surfactants.</a> <em style='font-style: italic'>Applied and Environmental Microbiology</em>. <b>71</b>, 6878-6884 (2005).</li><li>Polaczyk, A. L., Roberts, J. M., Hill, V. 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<p class='jove_content'>No competing financial interests. </p>
<p class='jove_content'>The views expressed in this article are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.</p>

<p class="jove_content"> 전기 양성 필터는 물에서 바이러스를 집중에 유용하다; 그러나 이러한 필터는 다시 자신의 효과를 변경할 수있는 그들의 구조와 구성이 다를 수 있습니다. 이 문제를 복잡하게, 캡시드 구조와 요금 농도 기술은 최적의 복구 <sup>(15)을</sup> 보장하기 위해 맞출 필요 바이러스 균주에 따라서 다릅니다. <em>(예를 들어,</em> 전기 양성 필터, 쇠고기 추출물 용출), 대상 바이러스의보다 효과적인 농도 <sup>...

<p class="jove_content"> 인간의 장내 바이러스는 수 인성 질병에 <sup>1-3의</sup> 중요한 원인이 요원하지만, 농도없이 자신의 검출이 어려워 일반적으로 오염 된 환경 바다에서 낮은 숫자에 존재한다. 바이러스를 농축하는데 사용 된 절차는 일반적으로 필터 용출액 여과 필터 뒤에 용출 단계, 및 보조 농도를 포함한다. 일반적인 여과 절차 (최근 <sup>4,5</sup> 검토) 등 전기 양성 필터와 같은 충전 세포막의 사용에 의존한다. 이 필터는 필터 표면 (양전하)과 대상 바이러스 입자 사이의 정전 기적 상호 작용을 사용하여 물에 현탁 바이러스를 캡처에 의존 (음전하). 시판되는 두 전성 필터가이 기술에 의존하는, 유리 / 셀룰로오스 나노 알루미나 / 유리 섬유 필터. 유리 / 셀룰로오스 필터 비용이 유리 (/ CE)의 사용을 제한하는 최대 10 배 나노 알루미나 / 유리 섬유의, 아르일상 바이러스 모니터링을위한 llulose 필터. 최근 연구에 싼 필터 대안의 사용을 정당화 차이가 주변 물 <sup>6,7에서</sup> 엔테로 바이러스의 회복이 두 필터 사이의 공칭 결론을 내렸다. 이러한 전성 유리 양모 필터와 같은 다른 필터 옵션 그러나, 그들은 하나의 소스 물 (전기 음성 필터)의 전처리가 필요하거나 (유리 양모 필터) 상업적으로 사용할 수 없습니다, 연구되고있다. 바이러스 농도 절차의 개발은 주로 물에서 바이러스 회수율을 향상시키기 위하여 기본 농도 기법 (필터)의 최적화에 초점을 맞추고있다. 그러나 볼륨 밀리리터 전형적으로 1 L로부터 얻은 용출액 부피를 감소 이차 농도 절차는 또한 바이러스 회수율 <sup>8에</sup> 상당한 영향을 미칠 수있다. </p><p class="jove_content"> 장용성 바이러스의 농도는 일반적으로 보조 소고기 추출물 일부 유형으로 응집제에 의존 (유기 floccu만큼은) 또는 무 지방 우유 응집 <sup>9-12</sup> 필터 표면에서 바이러스 입자를 제거합니다. 최근, 셀 라이트 (미세 입자)의 첨가와 결합 쇠고기 추출물을 사용하여 다른 농도 차 절차는 아데노 바이러스, 장내 바이러스, 및 노로 <sup>8,13,14의 회수</sup> 가능성을 보여 주었다. 이 바이러스 입자에 유기 응집 방법과 유사한 원리 하에서 셀 라이트 농도 작품에 부착 및 현탁액의 pH를 변경하여 입자 (플록 또는 셀 라이트)로부터 방출된다. 이 두 차의 농도 기술 사이의 비교가 아군 아데노 바이러스 (ADV) 유형 40, 41 <sup>(8)의</sup> 회복으로 평가되고있다.이 연구는 두 개의 보조 농도 기술은 아데노 바이러스의 복구에 통계적으로 차이가 없었다 결론을 내렸다. 그러나, 유기 응집 방법은 30 분을 필요로한다. pH가 3.5에서 배양, 셀 라이트 기술은 pH가 4.0에서 짧은 배양 (10 분)을 필요로한다. 유기 flocculat이온도 급 농도 중에 플록 입자를 수집 비싼 실험 장비 (원심)의 사용을 필요로, 반대로 셀 라이트 기술은 현탁액으로부터 셀 라이트 입자를 분리하는 기본적인 실험 장비 (진공 여과)를 사용한다. </p><p class="jove_content"> 필터와 이차 용출 기술 특정 조합은 또한 바이러스 회수율에 영향을 미칠 수있다. 한 연구는 주 (전기 양성 필터)의 특정 조합 및 보조 농도 기술 (셀 라이트 또는 유기 응집이) 아데노 바이러스 <sup>(13)의</sup> 회복에 상당한 영향을 미쳤다 결론을 내렸다. 이러한 연구 결과는 이러한 기술을 사용할 때 그 최적화가 최적으로 주어진 물 행렬로부터 대상 바이러스를 회수하기 위해 필요한 제안한다. 최적화는 여러 변수 (필터 유형 / 브랜드, 산도 용출 용액, 셀 라이트 / 유기 응집을) 평가되기 때문에, 힘든 과정을 많은 연구자들이 적극적으로 방지 걸리는 시간입니다. </p><p class="jove_content"> 이 초간각 바이러스 유형 고유 캡시드 형태 및 특정 캡시드 전하 보여주는데 tudy이 절차는 아마도 아군 인간 아데노 바이러스를 40 균주 41 이용한 물에서 바이러스 농도에 대한 최적의 조건을 식별하기 위해 개발되었다 농도 프로토콜은 모든 바이러스에 대해 최적화 될 필요가있다 최적 바이러스 복구를 달성하기 위하여 대상. 1) 전기 양성 필터 2 다음에 디스크) 보조 농도 셀 라이트 기술에 비해 설립 유기 응집 방법의 평가를 사용하여 수돗물의 바이러스 복구를 평가, 그리고 3) 평가 :이 연구는 ADV (40)에 의해 41 농도에 대한 접근 방법을 제공합니다 차 농도에 대한 용출 버퍼. </p>

<table><tbody><tr><td>Adenovirus 40 stock</td><td>ATCC</td><td>VR-931</td><td></td></tr><tr><td>Adenovirus 41 stock</td><td>ATCC</td><td>VR-930</td><td></td></tr><tr><td>Sodium Thiosulfate</td><td>Fluka Chemical Co.</td><td>72051</td><td></td></tr><tr><td>Celites #577</td><td>Fluka Chemical Co.</td><td>22142</td><td></td></tr><tr><td>NanoCeram 47 mm</td><td>Argonide</td><td>N/A</td><td></td></tr><tr><td>1MDS 47 mm</td><td>3M</td><td>6408502</td><td></td></tr><tr><td>AP-20 Prefilter 47 mm</td><td>Millipore Corp.</td><td>AP2004700</td><td></td></tr><tr><td>Glycine&amp;nbsp;</td><td>Sigma</td><td>50046-1KG</td><td></td></tr><tr><td>Sodium Polyphosphate</td><td>Acros Organics</td><td>390930010</td><td></td></tr><tr><td>Trypsin</td><td>Gibco</td><td>25200</td><td></td></tr><tr><td>PBS</td><td>Sigma</td><td>P5368</td><td></td></tr><tr><td>Hydrochloric Acid</td><td>Fisher</td><td>A481-212</td><td></td></tr><tr><td>BBL Beef Extract</td><td>BD Biosciences</td><td>212303</td><td></td></tr><tr><td>Difco Beef Extract</td><td>BD Biosciences</td><td>211520</td><td></td></tr><tr><td>ABI 7900 Real-time PCR system</td><td>ABI</td><td>N/A</td><td></td></tr><tr><td>Stainless Steel Filter Housing</td><td>Millipore Corp.</td><td>XX2004720</td><td></td></tr><tr><td>Blood DNA Extraction Kit</td><td>Qiagen&amp;nbsp;</td><td>51104</td><td></td></tr><tr><td>EPA MPN Calculator</td><td></td><td></td><td>http://www.epa.gov/nerlcwww/online.html</td></tr></tbody></table>

a small volume procedure for viral concentration from water

<p class='jove_content'>Small-scale concentration of viruses (sample volumes 1-10 L, here simulated with spiked 100 ml water samples) is an efficient, cost-effective way to identify optimal parameters for virus concentration. Viruses can be concentrated from water using filtration (electropositive, electronegative, glass wool or size exclusion), followed by secondary concentration with beef extract to release viruses from filter surfaces, and finally tertiary concentration resulting in a 5-30 ml volume virus concentrate. In order to identify optimal concentration procedures, two different electropositive filters were evaluated (a glass/cellulose filter [1MDS] and a nano-alumina/glass filter [NanoCeram]), as well as different secondary concentration techniques; the celite technique where three different celite particle sizes were evaluated (fine, medium and large) followed by comparing this technique with that of the established organic flocculation method. Various elution additives were also evaluated for their ability to enhance the release of adenovirus (AdV) particles from filter surfaces. Fine particle celite recovered similar levels of AdV40 and 41 to that of the established organic flocculation method when viral spikes were added during secondary concentration. The glass/cellulose filter recovered higher levels of both, AdV40 and 41, compared to that of a nano-alumina/glass fiber filter. Although not statistically significant, the addition of 0.1% sodium polyphosphate amended beef extract eluant recovered 10% more AdV particles compared to unamended beef extract. </p>

<html><p class="jove_content"> 셀 라이트 선택 </p><p class="jove_content"> 셀 라이트의 세 가지 다른 종류의 이전 실적이 가장 좋은 변종의 선택을 시험 하였다. 중간 크기의 입자를 미세과 Celites 가장 높은 아데노 바이러스 복구를 생산했다. 큰 celites의 사용은 AdV40 41 (범위 32 % -100 %) <strong>(그림 1)</strong> 모두 회수율 결과. 아데노 바이러스 (40)의 평균 회수율은 1백44퍼센트 ± 52 % (미세), 115 % ± 28 % (중간) 및 82 % ± 53 % (대형) 입자 ...

Watch this Scientific Journal Video about A Small Volume Procedure for Viral Concentration from Water at JoVE.com

A Small Volume Procedure for Viral Concentration from Water

<p class='jove_content'>An approach was developed for identifying optimal viral concentration conditions for small volume water samples using spikes of human adenovirus. The techniques described here are used to identify concentration parameters for other viral targets, and applied to large-scale viral concentration experimentation. </p>

물에서 바이러스 농도에 대한 작은 볼륨 절차

Small-scale concentration of viruses (sample volumes 1-10 L, here simulated with spiked 100 ml water samples) is an efficient, cost-effective way to ...

a-small-volume-procedure-for-viral-concentration-from-water

Universidad de Cartagena UDEC

Research

JoVE Journal

Environment

10.0K 조회수.  U.S. EPA. An approach was developed for identifying optimal viral concentration conditions for small volume water samples using spikes of human adenovirus. The techniques described here are used to identify concentration parameters for other viral targets, and applied to large-scale viral concentration experimentation. 

비디오: A Small Volume Procedure for Viral Concentration from Water

Steam Distillation

<p>Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Steam Distillation<button class="expand">Expand</button>
	<p>In this experiment, you will perform a steam distillation to extract an essential oil from an orange peel.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-2">
		<div class="lab-step">Before you start the lab, put on the appropriate personal protective equipment, including a lab coat, safety goggles, and gloves. This experiment must be performed in a hood.</div>
		</li>
		<li data-sub-note-item="1-3">
		<div class="lab-step">First, you will need to assemble the steam distillation apparatus. Check the apparatus set up by your instructor.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Set the two stands next to each other in the hood. Place the stir plate on the base of one of the stands and set the heating mantle on top of it. Plug the heating mantle into the temperature controller, but do not turn it on yet.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Now, obtain a watch glass with 3 dried orange peels from your instructor. Weigh the orange peels on the balance and record the mass of the orange peels in your notebook.
		<h4><strong>Table 1: Mass of essential oil recovered</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always" height="166" width="476">
			<tbody>
				<tr>
					<td>Temperature of steam distillation (&#176;C)</td>
					<td></td>
				</tr>
				<tr>
					<td>Mass of the orange peels (g)</td>
					<td>&#160; &#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
				</tr>
				<tr>
					<td>Mass of empty flask (g)</td>
					<td></td>
				</tr>
				<tr>
					<td>Mass of flask + essential oils (g)</td>
					<td></td>
				</tr>
				<tr>
					<td>Mass of essential oils (g)</td>
					<td></td>
				</tr>
				<tr>
					<td>Percent mass of essential oil recovered</td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/61/Table_1._Mass_of_essential_oil_recovered.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Bring your dried peels, funnel, spatula, and the 500-mL round-bottom flask to the instructor&#39;s bench and place the peels in the blender. Add about 4 mL of deionized water to the peels. Then, blend them until they are well mixed and smooth.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Using the funnel, transfer the blended peels to the round-bottom flask. Clamp the flask to the stand above the heating mantle.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Measure 200 mL of deionized water using your graduated cylinder and transfer it to the round-bottom flask using a funnel. Remove the funnel and add a stir bar to the flask.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Locate the Claisen adapter and apply a thin layer of grease to the joint. Then, insert the Claisen adapter into the flask.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Grease the thermometer adapter and insert it into the distilling head.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">Gently insert the thermometer into the distilling head by pushing and twisting through the adapter until the thermometer bulb is below the bend of the distilling head.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Lightly grease the lower joint of the distilling head, and then insert it into the outer arm of the Claisen adapter.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Now, obtain the condenser and carefully clamp it to the second stand. It should be oriented nearly horizontally, with the end closest to the distilling head slightly higher.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">Lightly grease the condenser and the side joint of the distilling head before connecting them.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Next, attach one piece of rubber tubing to the inlet of the condenser, which is the port furthest away from the distilling head. Attach the other end to the tap water faucet in the hood.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Connect the second piece of rubber tubing to the other port, which is the outlet, and place the end of the tubing in the drain.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Locate the separatory funnel and make sure that the stopcock is closed by turning it until it is fully horizontal.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">Insert the separatory funnel into the Claisen adapter, and add approximately 100 mL of deionized water to the funnel.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">Pick up the connecting joint and attach it to the end of the condenser.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Then, attach a 250-mL round-bottom flask to the connecting joint using a plastic clip.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">Finally, check all of the joints to make sure they are tightly connected and then secure each one with a plastic clip.</div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">Now that the steam distillation apparatus is fully assembled, start the procedure. First, slowly turn the tap water on to fill the condenser with water. <strong>Note</strong>: Be sure to turn the water on slowly, or the tubing may pop off and cause a flood.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Next, turn on the magnetic stirrer at the lowest setting and set the temperature controller to the appropriate setting to reach about 90 &#176;C.</div>
		</li>
		<li data-sub-note-item="1-24">
		<div class="lab-step">Once bubbles start forming in the mixture and liquid is dripping into the collection flask, adjust the heat to increase or decrease the rate of distillation to about 20 drops/min.</div>
		</li>
		<li data-sub-note-item="1-25">
		<div class="lab-step">Record the temperature on the thermometer in your notebook. Now, carefully open the stopcock on the separatory funnel to slowly add water to the flask. Your goal is to add water at the same rate as distillation, about 20 drops/min.</div>
		</li>
		<li data-sub-note-item="1-26">
		<div class="lab-step">Allow the distillation to proceed and collect about 50 mL of distillate.<strong> Note:</strong> Be patient, since this should take about 2 hours. The liquid in the flask will become less cloudy as more oil is collected.</div>
		</li>
		<li data-sub-note-item="1-27">
		<div class="lab-step">Once you have collected enough distillate, turn off the heat. Then, shut off the water to the condenser and carefully raise the entire setup.</div>
		</li>
		<li data-sub-note-item="1-28">
		<div class="lab-step">Allow it to cool completely before removing the heating mantle and disassembling the glassware.</div>
		</li>
		<li data-sub-note-item="1-29">
		<div class="lab-step">Empty the separatory funnel of any remaining water and pour the orange pulp down the drain.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Extraction of Essential Oil<button class="expand">Expand</button>
	<p>Liquid-liquid extraction is performed in a separatory funnel and is used to move a solute to another liquid in which it is more soluble. The two liquids must be immiscible and are usually an aqueous solution and a non-water-soluble organic liquid. Upon mixing, the solute is extracted into the other phase. Once the liquids settle into layers, they can be drained from the funnel one at a time.</p>
	<p>In the next part of the experiment, liquid-liquid extraction will be used to extract the essential oil from the water into an organic solvent. You&#39;ll then evaporate the organic solvent to recover the essential oil.</p>
	<ul class="lab-items">
		<li data-sub-note-item="2-3">
		<div class="lab-step">Before starting the experiment, first, make sure that the separatory funnel is rinsed and clean.</div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">Label the two 250-mL beakers as &#8216;organic layer&#8217; and &#8216;aqueous layer&#8217;. Then, attach a ring support to one of the stands.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Place the separatory funnel in the support. Make sure that the stopcock is closed and the separatory funnel is secure. Then, transfer the distillate into the separatory funnel.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">Measure 20 mL of diethyl ether at the instructor&#39;s hood and bring it back to your workstation. Pour the diethyl ether into the separatory funnel with the distillate. <strong>Note:</strong> You should see the immiscible liquids form two layers in the funnel. The top layer is the diethyl ether.</div>
		</li>
		<li data-sub-note-item="2-7">
		<div class="lab-step">Apply a thin layer of vacuum grease to the separatory funnel stopper and insert it into the top of the funnel.</div>
		</li>
		<li data-sub-note-item="2-8">
		<div class="lab-step">Hold the stopper in place and shake the separatory funnel vigorously for about 1 min.</div>
		</li>
		<li data-sub-note-item="2-9">
		<div class="lab-step">Occasionally, vent the funnel by turning it upside down and opening, then closing the stopcock. Be sure to do this inside of the hood and away from your face.</div>
		</li>
		<li data-sub-note-item="2-10">
		<div class="lab-step">Once you have finished mixing the contents, vent the funnel again, close the stopcock, and then place the funnel in the ring attached to the stand.</div>
		</li>
		<li data-sub-note-item="2-11">
		<div class="lab-step">Allow the aqueous and organic layers to fully separate. Then, place the aqueous layer beaker under the separatory funnel.</div>
		</li>
		<li data-sub-note-item="2-12">
		<div class="lab-step">Remove the stopper and slowly open the stopcock to drain the aqueous layer into the beaker. Carefully watch the solution drain and be sure to close the stopcock before the next layer is drained.</div>
		</li>
		<li data-sub-note-item="2-13">
		<div class="lab-step">Replace the aqueous layer beaker with the organic layer beaker. Open the stopcock and drain the organic layer into its beaker.</div>
		</li>
		<li data-sub-note-item="2-14">
		<div class="lab-step">Now, close the stopcock and return the contents of the aqueous layer beaker to the separatory funnel, add 20 mL of diethyl ether, and repeat the extraction.</div>
		</li>
		<li data-sub-note-item="2-15">
		<div class="lab-step">Open the stopcock and drain the aqueous layer into the appropriate beaker, and then drain the organic layer into the organic layer beaker, adding it to the organic layer from the first extraction.</div>
		</li>
		<li data-sub-note-item="2-16">
		<div class="lab-step">Now, obtain magnesium sulfate in a weighing boat and scoop a small spatula of it into the organic layer beaker. Swirl the beaker, and then let it sit for about 20 min.</div>
		</li>
		<li data-sub-note-item="2-17">
		<div class="lab-step">After 20 min, remove the separatory funnel and ring and mount a regular clamp to the lab stand.</div>
		</li>
		<li data-sub-note-item="2-18">
		<div class="lab-step">Weigh an empty 125-mL Erlenmeyer flask and record the mass in your notebook. Then, clamp the flask to the stand and place a conical glass funnel in its neck.</div>
		</li>
		<li data-sub-note-item="2-19">
		<div class="lab-step">Fold your filter paper in half and in half again. Then, open the filter paper on one side to create a cone. Place the cone inside the conical funnel.</div>
		</li>
		<li data-sub-note-item="2-20">
		<div class="lab-step">Now, filter the magnesium sulfate from the organic layer.</div>
		</li>
		<li data-sub-note-item="2-21">
		<div class="lab-step">Next, set your hot plate to 40 &#176;C and place a large beaker containing 400 mL of water on it. Place the Erlenmeyer flask in the warm water bath and allow the organic solvent to evaporate in the hood.</div>
		</li>
		<li data-sub-note-item="2-22">
		<div class="lab-step">Once the organic solvent has fully evaporated, remove the Erlenmeyer flask from the water bath and dry the outside with paper towels.</div>
		</li>
		<li data-sub-note-item="2-23">
		<div class="lab-step">Weigh the cooled flask and record the mass in your notebook.</div>
		</li>
		<li data-sub-note-item="2-24">
		<div class="lab-step">Now that the experiment is complete, be sure to properly clean up your workspace by disposing of all solutions in the non-halogenated waste.</div>
		</li>
		<li data-sub-note-item="2-25">
		<div class="lab-step">Wash all of the glassware using detergent and then rinse them with acetone and deionized water.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="3" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="3-1">
		<div class="lab-step">Determine the mass of the oil extracted from the orange peel by subtracting the mass of the empty flask from the mass of the flask with oil.</div>
		</li>
		<li data-sub-note-item="3-2">
		<div class="lab-step">Calculate the percentage of oil in the orange peel using the original mass of the dried peel. Typically, the steam distillation method recovers about 0.9 &#8211; 4 wt% of an orange peel&#8217;s mass as essential oil.</div>
		</li>
	</ul>
	<p>You distilled the essential oil in this lab at close to 100 &#176;C. The orange oil consists mainly of (+)limonene, which has a boiling point of 176 &#176;C. Thus, the steam distillation technique lets us extract it from the orange peel at a temperature that will not compromise its structure.</p>
	</li>
</ol>

Steam Distillation: Extraction of Essential Oil from Orange Peel - Procedure

증기 증류법

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Steam DistillationExpand
	In this experiment, you will ...

교육

JoVE Lab Manual

화학

Lab Manual Sub Articles

Extraction

Extraction: Liquid-Liquid and Acid-Base Extraction - Procedure

추출

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Cellulose RecoveryExpand
	Extraction and filtration can ...

Simple Distillation

<p>Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Simple Distillation<button class="expand">Expand</button>
	<p>In this lab, you will use simple distillation to separate a mixture of cyclohexane and toluene.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-2">
		<div class="lab-step">Before you start the lab, put on the appropriate personal protective equipment, including a lab coat, safety goggles, and gloves. This experiment must be conducted in a hood.</div>
		</li>
		<li data-sub-note-item="1-3">
		<div class="lab-step">Assemble the distillation apparatus. Refer to the example set up that has been prepared by your instructor.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Then, set up the two stands next to each other in the hood. Place the magnetic stirrer on the base of one of the stands.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Set the heating mantle on top of the magnetic stirrer, and then plug it into the temperature controller.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Add 5 &#8211; 10 mL of sand to the heating mantle. This will allow more homogeneous heating of the round-bottom flask. Clamp the round-bottom flask to the stand above the heating mantle.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Now, obtain cyclohexane and toluene from your instructor. Measure 2 mL of cyclohexane using a volumetric pipette and dispense it into the round-bottom flask.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Then, use a clean volumetric pipette to measure 2 mL of toluene and add it to the flask.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Carefully insert a thermometer into an adapter by gently pushing and twisting it through the top.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Lightly grease the adapter with vacuum grease and insert it into the distilling head. Make sure that the thermometer bulb is below the bend of the distilling head. Then, lightly grease the joints of the distilling head.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">Add a stir bar to the round-bottom flask and insert the distilling head into the round-bottom flask.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Now, clamp the condenser to the second stand with it oriented diagonally toward the side joint of the distilling head.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Connect one piece of tubing to the tap water faucet in the hood, and attach the other end to the inlet port of the condenser, which is located farthest from the distilling head.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">Attach the second tubing to the outlet port, which is located closest to the distilling head, and place the other end of the tubing into the drain.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Connect the condenser to the distilling head. Then, lightly grease the joint of the condenser and attach the connecting tube. Place a 10-mL graduated cylinder below the outlet of the tube.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Gently lower the setup until the round-bottom flask is seated in the sand in the heating mantle.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Double-check all of the connections on your setup to make sure that they are tight and oriented correctly. Secure each joint with a plastic clip.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">Now, slowly turn on the flow of water to the condenser. <strong>Note:</strong> Be careful not to turn on the water too quickly. If the water pressure is high, the tubing may pop off the condenser.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">Turn the magnetic stirrer to the lowest setting, and set the temperature controller to heat the mantle to just above 90 &#176;C.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Once bubbles start forming in the liquid mixture, adjust the heat until the distillation rate is about 2 drops/min. You should also see drops forming on the thermometer bulb.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">Record the temperature after every 2 drops that fall into the graduated cylinder or every minute.
		<h4><strong>Table 1: Distillation of toluene and cyclohexane</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td><strong>Time (min) </strong></td>
					<td><strong>Distilled volume (mL) </strong></td>
					<td><strong>Temperature (&#176;C) </strong></td>
				</tr>
				<tr>
					<td style="text-align: center;">1</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">2</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">3</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">4</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">5</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">6</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">7</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">8</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">9</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">10</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">11</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">12</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">13</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">14</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">15</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
			</tbody>
		</table>
		<a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/60/Table_1._Distillation_of_toluene_and_cyclohexane.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">When there is about 0.5 mL of the mixture remaining in the flask, which will look like a thin layer of liquid, turn off the heat and gently lift the glassware setup from the heating mantle. <strong>Note:</strong> Never heat the mixture until the flask is dry as this may cause an explosion.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Remove the stir plate with the heating mantle and set it aside.</div>
		</li>
		<li data-sub-note-item="1-24">
		<div class="lab-step">Then, turn off the water to the condenser and allow the setup to cool completely. When it is cool, carefully disassemble the glassware.</div>
		</li>
		<li data-sub-note-item="1-25">
		<div class="lab-step">Dispose of all solutions in the non-halogenated organic waste container. Clean your glassware with acetone followed by detergent and deionized water.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="2-1">
		<div class="lab-step">Plot the dew point temperature versus the distilled volume during the experiment. We see that drops start to fall into the collection vessel at ~ 81 &#176;C, which is the boiling point of cyclohexane. As the distillation progresses, the temperature increases to almost 111 &#176;C, which is the boiling point of toluene.</div>
		</li>
		<li data-sub-note-item="2-2">
		<div class="lab-step">Early in the distillation, the vapor is rich in cyclohexane. As the second milliliter is distilled, the temperature increases by ~ 20 &#176;C, which tells us that the amount of toluene in the vapor is increasing significantly. The temperature stabilizes as it approaches 111 &#176;C, which tells us that the vapor is rich in toluene towards the end of the distillation.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">Look at a boiling point diagram for cyclohexane and toluene, with the mole percent of cyclohexane and toluene on the x-axis and the temperature on the y-axis. The solid line denotes the bubble point, and the dashed line denotes the dew point.</div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">Use the dew point curve to determine the composition of the vapor throughout the distillation. For example, after 0.5 mL has been distilled, the condensing vapor is about 84 &#176;C. This corresponds to 95% cyclohexane on the dew point curve.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Once you know the composition of the vapor at each point, estimate the composition of the boiling mixture throughout the distillation. At room temperature, cyclohexane and toluene have nearly the same number of moles per milliliter, so think of the percentages in terms of volume.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">To determine how much of each liquid was distilled in each step, apply each percentage to the volume of liquid distilled since the previous measurement. This tells us that we distilled 1.9 mL of cyclohexane and 1.1 mL of toluene from our mixture of 2 mL of each liquid. Thus, our distillate was 63% cyclohexane and 37% toluene, and our remaining liquid mixture was 10% cyclohexane and 90% toluene.</div>
		</li>
	</ul>
	</li>
</ol>

Simple Distillation: Separation of a Mixture of Cyclohexane and Toluene - Procedure

간단한 증류

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Simple DistillationExpand
	In this lab, you will use ...

Scientific Measurement and Lab Skills

Two-Dimensional Graphs, Curve Fitting, and Standard Deviation - Procedure

과학적 측정 및 실험실 기술

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Measuring Diameter and CircumferenceExpand
	Error can be introduced in any experiment, even ...

Stoichiometry, Product Yield, and Limiting Reactants

화학량론(stoichiometry), 생성물 수율 및 제한 반응물(Limiting Reactants)

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Synthesis of tris(ethylenediamine)nickel chlorideExpand
	In this lab, you will combine nickel ...

Acid and Base Concentrations

<p>Source: Smaa Koraym at Johns Hopkins University, MD, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Preparation of ~0.1 M NaOH<button class="expand">Expand</button>
	<p>In the first part of the lab, you will use a 50% w/w solution of NaOH to prepare 500 mL of ~0.1 M. The 50% w/w NaOH is indicative of its weight ratio. For example, if the instructor prepared 150 mL of the 50% w/w NaOH solution, then 150 g of NaOH was dissolved in 150 g of water, and the total weight of the solution is 300 g.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-2">
		<div class="lab-step">To begin, put on the appropriate personal protective equipment, including gloves, chemical splash goggles, and a lab coat.</div>
		</li>
		<li data-sub-note-item="1-3">
		<div class="lab-step">Calculate the molarity of 50% w/w NaOH, which is M<sub>1</sub> in the dilution formula.<strong> Note: </strong>The density of 50% w/w NaOH is 1.53 g/mL, and the molar mass of NaOH is 39.998 g/mole.
		<h4>Table 1. Preparation of 0.1 M NaOH from 50% w/w NaOH</h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td>Density of 50% w/w stock solution</td>
					<td style="text-align: center;">1.53 g/mL</td>
				</tr>
				<tr>
					<td>Molar mass<sub>NaOH</sub></td>
					<td style="text-align: center;">39.998 g/mol</td>
				</tr>
				<tr>
					<td>Mass of NaOH in 50% w/w stock solution (mg)</td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>Total mass of 50% w/w stock solution</td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>Volume of 50% w/w stock solution (mL)</td>
					<td></td>
				</tr>
				<tr>
					<td>Moles of NaOH in 50% w/w solution (mol)</td>
					<td></td>
				</tr>
				<tr>
					<td>Molarity of 50% w/w stock solution (M<sub>1</sub>)</td>
					<td></td>
				</tr>
				<tr>
					<td>Volume of 50% w/w solution needed (V<sub>1</sub>)</td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/44/Table_1._Preparation_of_0.1_M_NaOH.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Use the dilution formula to determine the volume of 50% w/w NaOH needed to prepare 500 mL of ~0.1 M NaOH.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Label the 500 mL polyethylene bottle as &#8216;~0.1 M NaOH&#8217;.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Adjust the volume on a 1-mL pipette to the value calculated and use it to transfer the 50% w/w NaOH to the polyethylene bottle.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Use a 100-mL graduated cylinder to measure the amount of water and pour it into the bottle containing the NaOH. Cap the bottle and invert it several times to mix the solution. <strong>Note:</strong> You will need 500 mL minus the calculated volume of NaOH.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Standardization of 0.1 M NaOH<button class="expand">Expand</button>
	<p>After you have prepared 0.1 M NaOH, determine its exact concentration, or standardize it, using the acid-base titration method. In this technique, a base like NaOH is slowly added to an acid like potassium hydrogen phthalate (KHP). The chemical reaction that takes place in the flask is a neutralization reaction. In this neutralization reaction, one mole of base neutralizes one mole of acid, resulting in salt and water. This reaction is performed in the presence of the indicator phenolphthalein, which is colorless at the start of the reaction when the pH is acidic. The indicator turns pink as soon as enough NaOH is added to the flask to make the pH basic.</p>
	<ul class="lab-items">
		<li data-sub-note-item="2-2">
		<div class="lab-step">Label the three Erlenmeyer flasks as &#8216;A&#8217;, &#8216;B&#8217;, and &#8216;C&#8217;.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">Weigh 0.5 &#8211; 0.7 g of KHP for each of the flasks and record the mass for each. <strong>Note: </strong>Try to measure the same mass of KHP for all three flasks.
		<h4><strong>Table 2. Standardization of NaOH</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td><strong>Molar mass<sub>KHP</sub> = 204.23 g/mol </strong></td>
					<td style="text-align: center;"><strong>Flask A</strong></td>
					<td style="text-align: center;"><strong>Flask B</strong></td>
					<td style="text-align: center;"><strong>Flask C</strong></td>
				</tr>
				<tr>
					<td>Mass of KHP (g)</td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Volume<sub>initial NaOH</sub>(mL)</td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Volume<sub>final NaOH</sub> (mL)</td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Volume<sub>NaOH</sub> (mL)</td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Moles of KHP</td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Moles of NaOH</td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Molarity of NaOH</td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Average molarity</td>
					<td></td>
				</tr>
				<tr>
					<td>Standard deviation</td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/44/Table_2._Standardization_of_NaOH.xlsx" target="_blank">Click Here to download Table 2</a></div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">Add 50 mL of deionized water to each flask, and use a glass stirring rod to stir the solutions until they appear homogeneous.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Add 2-3 drops of phenolphthalein to each of the three flasks.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">Set up the titration apparatus. Attach the burette clamp to the ring stand, and securely clamp the 50-mL glass burette to it. Make sure the valve of the burette is closed.</div>
		</li>
		<li data-sub-note-item="2-7">
		<div class="lab-step">Label a 400-mL beaker as &#8216;waste&#8217; and place it under the burette. Rinse the burette by pouring about 5 mL of 0.1 M NaOH into the burette. Open the burette valve to allow the NaOH to flow into the beaker.</div>
		</li>
		<li data-sub-note-item="2-8">
		<div class="lab-step">Close the valve and fill the burette with slightly more than 50 mL of NaOH. Release any air bubbles present in the tip of the burette by opening and closing the burette valve. Record the starting volume of NaOH.</div>
		</li>
		<li data-sub-note-item="2-9">
		<div class="lab-step">Place flask A below the tip of the burette, and titrate the solution using 1 mL volumes of NaOH. Swirl the solution after each addition. Continue adding 1 mL volumes to the flask until the pink color persists. This is considered the endpoint. Record the volume of 0.1 M NaOH added to achieve the endpoint.</div>
		</li>
		<li data-sub-note-item="2-10">
		<div class="lab-step">Repeat the titration for flasks B and C. This data will be used to calculate the actual concentration of NaOH.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="3" data-parent-collapse="">Titration of phosphoric acid<button class="expand">Expand</button>
	<p>In this experiment, we will determine two of the three pKa values for the triprotic acid, phosphoric acid, using acid-base titration. In this neutralization reaction, phosphoric acid reacts with NaOH to form water and the salt, sodium phosphate.</p>
	<ul class="lab-items">
		<li data-sub-note-item="3-2">
		<div class="lab-step">Attach the drop counter to the ring stand, below the burette clamp. Secure the plastic burette so that its tip is just above the drop counter.</div>
		</li>
		<li data-sub-note-item="3-3">
		<div class="lab-step">Connect the drop counter to the data acquisition system, and make sure the two valves of the plastic burette are both in the closed position.</div>
		</li>
		<li data-sub-note-item="3-4">
		<div class="lab-step">Place the waste container below the burette and pour a few mL of 0.1 M NaOH into the burette. Open both valves to drain the NaOH into the waste beaker. Then close the valves.</div>
		</li>
		<li data-sub-note-item="3-5">
		<div class="lab-step">Fill the plastic burette with 25 mL of 0.1 M NaOH. Drain about 5 mL into the waste beaker&#8212;enough so that NaOH fills the burette tip. Make sure there are no air bubbles, then close the valves.</div>
		</li>
		<li data-sub-note-item="3-6">
		<div class="lab-step">Calibrate the drop counter. Replace the waste beaker beneath the burette with a 10-mL graduated cylinder. Then, open the bottom valve on the burette, while keeping the top valve closed. Turn on the data acquisition system and set it to &#8216;drop counting mode&#8217;.</div>
		</li>
		<li data-sub-note-item="3-7">
		<div class="lab-step">Slowly open the top valve to very slowly release drops, ideally at one drop every 2 s. Allow the drops to empty from the burette until there is 9-10 mL of 0.1 M NaOH in the graduated cylinder.</div>
		</li>
		<li data-sub-note-item="3-8">
		<div class="lab-step">Close the bottom valve and leave the top valve as is. Read the volume of NaOH in the graduated cylinder to the first decimal place and enter this value in the data acquisition system. Record the value for &#8216;drops/mL&#8217;. Then, discard the NaOH in the graduated cylinder into the aqueous waste beaker.</div>
		</li>
		<li data-sub-note-item="3-9">
		<div class="lab-step">Calibrate the pH sensor before starting the titration. Connect the pH sensor to the data acquisition system, then select &#39;Calibrate&#39;. Rinse the bulb of the pH sensor with deionized water before inserting it into the pH 7 buffer. Leave the sensor submerged until the voltage stabilizes, then accept the measurement.</div>
		</li>
		<li data-sub-note-item="3-10">
		<div class="lab-step">Rinse the bulb with deionized water and insert it into the pH 10 buffer. Allow the voltage to stabilize, then accept the measurement.</div>
		</li>
		<li data-sub-note-item="3-11">
		<div class="lab-step">Rinse the bulb of the pH sensor again and slide it through the designated slot in the drop counter.</div>
		</li>
		<li data-sub-note-item="3-12">
		<div class="lab-step">Measure 40 mL of deionized water into a clean 100-mL beaker, then, transfer 1 mL of phosphoric acid into the beaker of water.</div>
		</li>
		<li data-sub-note-item="3-13">
		<div class="lab-step">Place the beaker on the stir plate under the drop counter. Carefully slide the pH sensor into the beaker.</div>
		</li>
		<li data-sub-note-item="3-14">
		<div class="lab-step">Add a stir bar to the beaker, and turn the stir setting onto high. Start collecting data on the acquisition device. Then, open the bottom valve on the burette. <strong>Note: </strong>The drop rate should be about 1 drop every 2 s. After the first drop is released, check to see data are being recorded.</div>
		</li>
		<li data-sub-note-item="3-15">
		<div class="lab-step">Continue the titration until the pH meter reads pH 12. Then, stop acquiring data and close the valve on the burette. Save your data on a flash drive.</div>
		</li>
		<li data-sub-note-item="3-16">
		<div class="lab-step">To clean up your workspace, check the pH of all waste solutions using pH paper. Neutralize all acidic aqueous waste with baking soda and all basic waste with citric acid. Add enough of either baking soda or citric acid to the solution until it stops bubbling.</div>
		</li>
		<li data-sub-note-item="3-17">
		<div class="lab-step">Flush all neutralized solutions down the sink with copious amounts of water.</div>
		</li>
		<li data-sub-note-item="3-18">
		<div class="lab-step">Wash all glassware.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="4" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="4-1">
		<div class="lab-step">In the first part of this lab, you standardized a solution of NaOH using KHP to determine its actual concentration. Now, let&#39;s see how close the standardized concentration is to the 0.1 M concentration that was prepared. Determine the number of moles of KHP that was added to each flask, and by extension, the moles of NaOH. Once the solution is neutralized, the molar quantities of KHP and NaOH are equal.</div>
		</li>
		<li data-sub-note-item="4-2">
		<div class="lab-step">Calculate the molarity of NaOH based on the total volume of NaOH that was added to each flask. The actual concentration is lower than the expected 0.1 molarity. This is because NaOH is hygroscopic, so it is difficult to weigh it accurately.</div>
		</li>
		<li data-sub-note-item="4-3">
		<div class="lab-step">Plot the results for the phosphoric acid titration (pH vs. Volume of NaOH). Phosphoric acid is a weak triprotic acid, meaning that it has the potential to provide three protons per molecule when it dissociates in aqueous solutions. Phosphoric acid has three pKa values, one for when each proton is dissociated.</div>
		</li>
		<li data-sub-note-item="4-4">
		<div class="lab-step">Look at the data. There are two sigmoidal curves, indicating two equivalence points. Each equivalence point corresponds to a dissociation constant, Ka, of phosphoric acid. <strong>Note: </strong>You stopped the experiment once the pH reached 12, so you only measured two of the three Ka values.</div>
		</li>
		<li data-sub-note-item="4-5">
		<div class="lab-step">Plot the first derivative of the titration curve. The equivalence points are represented by the curve maximums.
		<h4><strong>Table 3. Titration of phosphoric acid</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td>Volume<sub>1<sup>st</sup> equivalence point</sub> (mL)</td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>Volume<sub>1<sup>st</sup> half-equivalence point</sub> (mL)</td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>Volume<sub>2<sup>nd</sup> equivalence point</sub> (mL)</td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>Volume<sub>2<sup>nd</sup> half-equivalence point</sub> (mL)</td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>1<sup>st</sup> pKa<sub>measured</sub></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>1<sup>st</sup> pKa<sub>theoretical</sub></td>
					<td style="text-align: center;">2.16</td>
				</tr>
				<tr>
					<td>2<sup>nd</sup> pKa<sub>measured</sub></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>2<sup>nd</sup> pKa<sub>theoretical</sub></td>
					<td style="text-align: center;">7.21</td>
				</tr>
				<tr>
					<td>Moles of NaOH</td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>Moles of H<sub>3</sub>PO<sub>4</sub></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>Molarity of H<sub>3</sub>PO<sub>4</sub></td>
					<td style="text-align: center;"></td>
				</tr>
			</tbody>
		</table>
		<a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/44/Table_3._Titration_of_Phosphoric_Acid.xlsx" target="_blank">Click Here to download Table 3</a></div>
		</li>
		<li data-sub-note-item="4-6">
		<div class="lab-step">Find the first half-equivalence point by taking the volume of NaOH corresponding to the first equivalence point and dividing it by 2. At the half-equivalence point, the concentrations of undissociated acid and its conjugate base are the same, and the pH is equal to the pKa.</div>
		</li>
		<li data-sub-note-item="4-7">
		<div class="lab-step">Look up the pH at this volume from your table of data to get a more precise value. This corresponds to the first pKa, which is reported in the literature as 2.16.</div>
		</li>
		<li data-sub-note-item="4-8">
		<div class="lab-step">Repeat this to find the second pKa. The second half-equivalence point is located midway between the first and second equivalence points, which should give a pKa of about 7.2.</div>
		</li>
	</ul>
	</li>
</ol>

Acid-Base Titration: Calculating pH, Strength, and Concentration - Procedure

산 및 염기 농도

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Preparation of ~0.1 M NaOHExpand
	In the first part of the lab, you will use a 50% w/w solution ...

Solubility

Solubility: Solubility Equilibrium and Thermodynamics - Procedure

가용성

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Creating a Saturated SolutionExpand
	In this experiment, you will create a saturated solution ...

Concentration Dependence

<p>Source: Smaa Koraym at Johns Hopkins University, MD, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Concentration Dependence<button class="expand">Expand</button>
	<p>In this experiment, you will combine varying concentrations of aqueous HCl and sodium thiosulfate to make solid sulfur, which rapidly gathers into opaque yellow particles at a certain sulfur concentration. Since the reaction solution starts clear and colorless, you can easily tell when it reaches that concentration.</p>
	<p>You&#39;ll use the same test tube and total volume each time, so it will take the same amount of sulfur to make each solution completely opaque. Thus, you&#39;ll measure the reaction progress by timing how long that takes. You&#39;ll then use that data to estimate the reaction orders of the individual reactants and of the overall reaction.</p>
	<p>Before starting the lab, make a table listing the reactant concentrations, the time to solution opacity, and the solution temperature for the trials.</p>
	<h4><strong>Table 1: Reaction progress</strong></h4>
	<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
		<tbody>
			<tr>
				<td><strong>Trial</strong></td>
				<td><strong>[Na<sub>2</sub>S<sub>2</sub>O<sub>3</sub>] (M)</strong></td>
				<td><strong>[HCl] (M)</strong></td>
				<td><strong>Time (s)</strong></td>
				<td><strong>Temp (&#176;C)</strong></td>
			</tr>
			<tr>
				<td style="text-align: center;">1</td>
				<td style="text-align: center;">0.1 M</td>
				<td style="text-align: center;">3.0 M</td>
				<td></td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">2</td>
				<td style="text-align: center;">0.1 M</td>
				<td style="text-align: center;">3.0 M</td>
				<td></td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">3</td>
				<td style="text-align: center;">0.2 M</td>
				<td style="text-align: center;">3.0 M</td>
				<td></td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">4</td>
				<td style="text-align: center;">0.15 M</td>
				<td style="text-align: center;">3.0 M</td>
				<td></td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">5</td>
				<td style="text-align: center;">0.05 M</td>
				<td style="text-align: center;">3.0 M</td>
				<td></td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">6</td>
				<td style="text-align: center;">0.1 M</td>
				<td style="text-align: center;">6.0 M</td>
				<td></td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">7</td>
				<td style="text-align: center;">0.1 M</td>
				<td style="text-align: center;">4.5 M</td>
				<td></td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">8</td>
				<td style="text-align: center;">0.1 M</td>
				<td style="text-align: center;">1.5 M</td>
				<td></td>
				<td></td>
			</tr>
		</tbody>
	</table>
	<p><a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/50/Table_1._Reaction_progress.xlsx" target="_blank">Click Here to download Table 1</a></p>
	<p>We want to make sure that the reactions are all taking place at room temperature. You&#39;ll perform two benchmark trials, three trials with different sodium thiosulfate concentrations, and three trials with different HCl concentrations. You will vary the concentrations by diluting stock solutions of sodium thiosulfate and HCl, as shown in the following tables.</p>
	<h4><strong>Table 2: Sodium thiosulfate dilutions</strong></h4>
	<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
		<tbody>
			<tr>
				<td style="text-align: center;"><strong>Target Concentration</strong></td>
				<td style="text-align: center;"><strong>Volume of 0.2 M sodium thiosulfate</strong></td>
				<td style="text-align: center;"><strong>Volume of DI water</strong></td>
			</tr>
			<tr>
				<td style="text-align: center;">0.05 M</td>
				<td style="text-align: center;">5 mL</td>
				<td style="text-align: center;">15 mL</td>
			</tr>
			<tr>
				<td style="text-align: center;">0.10 M</td>
				<td style="text-align: center;">10 mL</td>
				<td style="text-align: center;">10 mL</td>
			</tr>
			<tr>
				<td style="text-align: center;">0.15 M</td>
				<td style="text-align: center;">15 mL</td>
				<td style="text-align: center;">5 mL</td>
			</tr>
			<tr>
				<td style="text-align: center;">0.20 M</td>
				<td style="text-align: center;">20 mL</td>
				<td style="text-align: center;">0 mL</td>
			</tr>
		</tbody>
	</table>
	<p><a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/50/Table_2._Sodium_thiosulfate_dilutions.xlsx" target="_blank">Click Here to download Table 2</a></p>
	<h4><strong>Table 3: HCl Dilutions</strong></h4>
	<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
		<tbody>
			<tr>
				<td style="text-align: center;"><strong>Target Concentration</strong></td>
				<td style="text-align: center;"><strong>Volume of 6.0 M HCl</strong></td>
				<td style="text-align: center;"><strong>Volume of DI water</strong></td>
			</tr>
			<tr>
				<td style="text-align: center;">1.5 M</td>
				<td style="text-align: center;">2.5 mL</td>
				<td style="text-align: center;">7.5 mL</td>
			</tr>
			<tr>
				<td style="text-align: center;">3.0 M</td>
				<td style="text-align: center;">5.0 mL</td>
				<td style="text-align: center;">5.0 mL</td>
			</tr>
			<tr>
				<td style="text-align: center;">4.5 M</td>
				<td style="text-align: center;">7.5 mL</td>
				<td style="text-align: center;">2.5 mL</td>
			</tr>
			<tr>
				<td style="text-align: center;">6.0 M</td>
				<td style="text-align: center;">10 mL</td>
				<td style="text-align: center;">0 mL</td>
			</tr>
		</tbody>
	</table>
	<p><a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/50/Table_3._HCl_Dilutions.xlsx" target="_blank">Click Here to download Table 3</a></p>
	<p>Remember to use caution when handling HCl, which is toxic and highly corrosive. Sulfur dioxide, which is a gaseous product of this reaction, is also toxic. You will leave the reaction waste in the fume hood overnight to let the sulfur dioxide escape harmlessly.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-6">
		<div class="lab-step">First, put on a lab coat, splash-proof safety glasses, and nitrile gloves.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Fill a plastic wash bottle with deionized water and get a test tube marked with an X.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Clamp the test tube over the center of a small stir plate. The label must be on the opposite side from you. Make sure that you can clearly see the X. Place a small magnetic stir bar in the test tube.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Use a thermometer clamp to secure a glass thermometer in the lower third of the tube, keeping it clear of the X and the stir bar.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Cut a sheet of about 20 squares of plastic paraffin film from a roll and bring the sheet back to your hood.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">Lay paper towels in the fume hood as a clean surface for labware to be reused.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Label a 600-mL beaker as &#8216;waste&#8217; for the reaction, a 100-mL beaker as &#8216;0.2 M sodium thiosulfate&#8217;, and a 50-mL beaker as &#8216;6 M HCl&#8217;.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Fill the 100-mL beaker with 0.2 M sodium thiosulfate from the stock bottle in the dispensing hood.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">After that, bring the 50-mL beaker and a watch glass to the acid-dispensing hood to obtain 50 mL of 6 M HCl. Cover the filled beaker with the watch glass and bring your portion of HCl back to your hood.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Prepare 20 mL of 0.1 M sodium thiosulfate for the first benchmark trial. Use a 10-mL volumetric pipette to measure 10 mL of 0.2 M sodium thiosulfate and dispense it into a 20-mL volumetric flask. Fill the 20-mL volumetric flask with deionized water to the mark.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Then, cut a square of plastic paraffin film, seal the flask, and invert it several times to thoroughly mix the solution.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Remove the film and pour the solution into the test tube.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">Prepare 10 mL of 3 M HCl. Pipette 5 mL of 6 M HCl into a 10-mL graduated cylinder. Add deionized water to fill the graduated cylinder to the 10-mL line.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">Seal the top of the graduated cylinder with plastic paraffin film and thoroughly mix the HCl solution by inverting it several times.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Now, start the stir motor and get a reset stopwatch. Confirm that you can see the X through the solution in the test tube.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">Simultaneously start the stopwatch and pour the 3 M HCl into the test tube.</div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">Watch the X through the solution, which will start becoming cloudy when enough sulfur has been produced to saturate it. Stop the stopwatch exactly when the solution becomes so opaque that the X disappears.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Record the time in your lab notebook for benchmark trial 1 and then reset the stopwatch. Also, record the temperature of the solution.</div>
		</li>
		<li data-sub-note-item="1-24">
		<div class="lab-step">Now, turn off the stir motor, remove the thermometer, and rinse it with deionized water into the waste beaker.</div>
		</li>
		<li data-sub-note-item="1-25">
		<div class="lab-step">Then, empty the test tube into the waste beaker, retrieve the stir bar with long forceps, and rinse the test tube and stir bar with deionized water.</div>
		</li>
		<li data-sub-note-item="1-26">
		<div class="lab-step">Thoroughly clean the test tube with a test tube brush. Briefly rinse the volumetric flask and graduated cylinder with deionized water as well. Dry everything with paper towels.</div>
		</li>
		<li data-sub-note-item="1-27">
		<div class="lab-step">Repeat the trial in the exact same way for the second benchmark time. If the time is not within 3 - 5 s of the first trial, repeat the benchmark trial until you have two consistent trials.</div>
		</li>
		<li data-sub-note-item="1-28">
		<div class="lab-step">Follow the same overall procedure for each subsequent trial, changing the dilutions as indicated in your table and cleaning your glassware between each trial. Use a 5-mL volumetric pipette as needed when measuring the sodium thiosulfate stock solution in trials four and five.</div>
		</li>
		<li data-sub-note-item="1-29">
		<div class="lab-step">Once you have performed all eight trials, rinse your glassware and tools one last time and neutralize the reaction waste with baking soda. Use caution because sulfur dioxide is one of the reaction products.</div>
		</li>
		<li data-sub-note-item="1-30">
		<div class="lab-step">Transfer the neutralized reaction waste to the designated waste container. Then, pour any remaining sodium thiosulfate solution into its labeled waste container and rinse the beaker with deionized water.</div>
		</li>
		<li data-sub-note-item="1-31">
		<div class="lab-step">Neutralize any remaining HCl with baking soda before flushing it down the drain with tap water.</div>
		</li>
		<li data-sub-note-item="1-32">
		<div class="lab-step">Finally, clean and put away your labware according to your standard practices and throw out any trash remaining in your hood. Your instructor will dispose of the reaction waste later.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="2-1">
		<div class="lab-step">Now, estimate the reaction order of sodium thiosulfate and HCl. Calculate the starting concentration of sodium thiosulfate in the reaction mixture for trials 1 through 5. Looking at the concentration of sodium thiosulfate and the reaction times, we see that as the concentration doubles, the time to opacity is halved.
		<h4><strong>Table 4: Estimating reaction order sodium thiosulfate</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td style="text-align: center;"><strong>Trial</strong></td>
					<td style="text-align: center;"><strong>[Na<sub>2</sub>S<sub>2</sub>O<sub>3</sub>] added</strong></td>
					<td style="text-align: center;"><strong>Na<sub>2</sub>S<sub>2</sub>O<sub>3</sub> volume (mL)</strong></td>
					<td style="text-align: center;"><strong>Total volume (mL)</strong></td>
					<td style="text-align: center;"><strong>[Na<sub>2</sub>S<sub>2</sub>O<sub>3</sub>] in mixture </strong></td>
					<td style="text-align: center;"><strong>Time (s)</strong></td>
					<td style="text-align: center;"><strong>Inverse time (s<sup>-1</sup>)</strong></td>
				</tr>
				<tr>
					<td style="text-align: center;">1, 2</td>
					<td style="text-align: center;">0.1</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">3</td>
					<td style="text-align: center;">0.2</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">4</td>
					<td style="text-align: center;">0.15</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">5</td>
					<td style="text-align: center;">0.05</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
			</tbody>
		</table>
		<a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/50/Table_4._Estimating_reaction_order_sodium_thiosulfate.xlsx" target="_blank">Click Here to download Table 4</a></div>
		</li>
		<li data-sub-note-item="2-2">
		<div class="lab-step">Remember that each trial used the same volume, so it took the same amount of sulfur to make each solution opaque. Thus, the reaction is twice as fast when the sodium thiosulfate concentration is doubled.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">When the concentration increases by a factor of 4, the reaction rate also increases by a factor of 4. This one-to-one relationship suggests that the reaction was first order for sodium thiosulfate. If so, we would expect a plot of rate versus sodium thiosulfate concentration to be linear.</div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">We didn&#39;t measure how much sulfur it took to turn the solution opaque, but we assume that it was the same for each trial. This lets us use the inverse of time to opacity as a stand-in for the rate. The slope won&#39;t be equal to k, but that&#39;s OK for this lab.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Plot inverse reaction time as a function of sodium thiosulfate concentration. This confirms the linear relationship between sulfur production and thiosulfate concentration. Thus, the reaction seems to be first order with respect to thiosulfate.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">Use the same method to estimate the reaction order of HCl. First, calculate the starting concentration of HCl in the benchmark trials and in trials 6 through 8.
		<h4><strong>Table 5: Estimating reaction order HCl</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td style="text-align: center;"><strong>Trial</strong></td>
					<td style="text-align: center;"><strong>[HCl] added</strong></td>
					<td style="text-align: center;"><strong>HCl volume (mL) </strong></td>
					<td style="text-align: center;"><strong>Total volume (mL) </strong></td>
					<td style="text-align: center;"><strong>[HCl] in mixture </strong></td>
					<td style="text-align: center;"><strong>Time (s)</strong></td>
				</tr>
				<tr>
					<td style="text-align: center;">1, 2</td>
					<td style="text-align: center;">0.1</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">3</td>
					<td style="text-align: center;">0.2</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">4</td>
					<td style="text-align: center;">0.15</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">5</td>
					<td style="text-align: center;">0.05</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
			</tbody>
		</table>
		<a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/50/Table_5._Estimating_reaction_order_HCl.xlsx" target="_blank">Click Here to download Table 5</a></div>
		</li>
		<li data-sub-note-item="2-7">
		<div class="lab-step">Then, look at the concentration of HCl and the reaction times for these trials. The reaction times are nearly identical, so the HCl concentration has no effect on the reaction rate. This means that HCl seems to be zeroth order for this reaction.</div>
		</li>
		<li data-sub-note-item="2-8">
		<div class="lab-step">Lastly, add up the reaction orders of the reactants to get the overall reaction order.</div>
		</li>
	</ul>
	</li>
</ol>

Concentration Dependence and Reaction Order - Procedure

집중 의존성

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Concentration DependenceExpand
	In this experiment, you will combine varying concentrations of ...

Basic Organic Chemistry Techniques

<p>Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Synthesis of Benzoic Acid<button class="expand">Expand</button>
	<p>In this lab, you&#39;ll learn several important techniques that you&#39;ll use throughout this class. This includes measuring the mass or volume of reactants and products, methods of heating and cooling reaction mixtures, proper selection and handling of glassware, and separating solids and liquids by vacuum filtration. First, you&#39;ll synthesize benzoic acid by protonating sodium benzoate with hydrochloric acid, or HCl, using water as the solvent. Sodium benzoate is very soluble in water, but benzoic acid is not, so you can filter the solid product out of the solution.</p>
	<p>You&#39;ll use vacuum filtration, which is used for powdery solids, to filter out the benzoic acid. Benzoic acid is less soluble in water at lower temperatures, so you&#39;ll collect more product if you cool the reaction solution before you filter it. When you do this lab, remember that HCl is toxic and a strong acid. It&#39;s always best to work with strong acids and organic solvents in a fume hood. If you spill any HCl, follow your lab&#39;s procedures for neutralizing and cleaning up strong acids.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-3">
		<div class="lab-step">Put on a lab coat, safety glasses, and nitrile gloves. Change your gloves if you get acid or organic solvent on them.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Bring a clean 50-mL beaker and your lab notebook to the balance, and then tare a clean empty weighing boat on the balance.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Use a clean spatula to measure out ~2 g of sodium benzoate.<strong> Note:</strong> Stay between 1.9 and 2.1 g.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Dispose of any extra sodium benzoate into the appropriate waste container. Close the bottle of sodium benzoate when you&#39;re done with it.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Write down the mass of sodium benzoate and pour it into your beaker. Clean the spatula with a lab wipe so that it can be used again and return to your fume hood.
		<h4><strong>Table 1: Reaction yield of benzoic acid</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td style="text-align: center;"><strong>Mass of sodium<br />
					benzoate (g)</strong></td>
					<td style="text-align: center;"><strong>Moles of sodium<br />
					benzoate</strong></td>
					<td style="text-align: center;"><strong>Volume of<br />
					HCl (mL)</strong></td>
					<td style="text-align: center;"><strong>Moles of<br />
					HCl</strong></td>
					<td style="text-align: center;"><strong>Moles of benzoic<br />
					acid</strong></td>
					<td style="text-align: center;"><strong>Mass of benzoic<br />
					acid (g)</strong></td>
				</tr>
				<tr>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td><strong>Theoretical yield</strong></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">-</td>
					<td style="text-align: center;">-</td>
					<td style="text-align: center;">-</td>
					<td style="text-align: center;">-</td>
					<td><strong>Percent yield</strong></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/56/Table_1._Reaction_yield_of_benzoic_acid.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Get a clean 10-mL graduated cylinder and measure 10 mL of deionized water. Pour the water into the beaker of sodium benzoate. Stir the solution with a glass rod until the sodium benzoate has completely dissolved.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Obtain a clean 5-mL graduated cylinder and measure 5 mL of 3 M HCl. <strong>Note: </strong>If you pour too much, use a Pasteur pipette to transfer the excess to a small beaker labeled &#8216;acid waste&#8217;. Close the bottle and put it back when you&#39;re done.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Use a clean Pasteur pipette to draw up a small amount of HCl from your graduated cylinder. Start adding the HCl to the sodium benzoate solution at a rate of about one drop every 6 seconds or 10 drops/min. Stir the solution frequently with the glass rod. This should take about 10 min. <strong>Note:</strong> As you add more HCl, you&#39;ll start to see benzoic acid precipitating from the solution.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">When you are done, fill a 600-mL beaker about halfway with crushed ice and add tap water to just fill the spaces between the ice to make an ice bath.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Place the ice bath by a lab stand in your fume hood and use a medium clamp to hold the reaction beaker in the bath. Make sure that the surface of the solution is below the ice.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Clamp a thermometer in the reaction solution.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">While the reaction cools, obtain 25 mL of deionized water in a 50-mL graduated cylinder. Place the graduated cylinder in a 600-mL beaker and pack ice around it to cool the water.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Once the reaction solution reaches 10 &#176;C, it&#39;s ready to be filtered. Set up another lab stand and obtain a clean 250-mL filter flask. Clamp the flask upright on the lab stand.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Ensure that your vacuum tubing is connected to the vacuum source, and then carefully push the free end of the tubing onto the barbed arm of the flask.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Place a rubber adapter and a B&#252;chner funnel in the mouth of the flask. Confirm that the reaction solution has reached 10 &#176;C and remove the thermometer from the beaker.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">Obtain a piece of circular filter paper and place it in the B&#252;chner funnel so that the small holes are completely covered.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">Get a new Pasteur pipette, and use a few drops of cold deionized water to wet the filter paper. <strong>Note: </strong>This helps keep the filter paper in place when you pour the solution into the funnel.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Open the vacuum line part way to reduce the pressure in the flask.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">Remove the beaker from the ice bath, stir the solution well with the glass rod until the solid is swirling around in the liquid, and then slowly pour it onto the filter paper. <strong>Note:</strong> If the liquid does not move quickly through the funnel, make sure that there are no gaps between the funnel, adapter, and flask, and then gradually open the vacuum until the liquid rapidly flows into the flask.</div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">Use a clean Pasteur pipette to rinse the inner walls of the beaker with ~10 mL of cold deionized water and pour the rinse into the funnel. Pour the rest of the cold deionized water over the benzoic acid on the filter to wash it. <strong>Note:</strong> This is an important step that removes impurities, side products, and unreacted compounds.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Leave the benzoic acid in the funnel with the vacuum running until it is completely dry. <strong>Note: </strong>This usually takes ~2 h, so let&#39;s continue to the second half of the lab in the meantime.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Refluxing Tetrahydrofuran (THF) and Measuring Product Mass<button class="expand">Expand</button>
	<p>While your benzoic acid dries, you&#39;ll practice refluxing tetrahydrofuran, or THF, which has a boiling point of 66 &#176;C. THF is volatile, flammable, and an irritant, so avoid letting it touch your skin and always work with it in a fume hood. Refluxing is a technique that constantly condenses the vapor and returns it to the flask. This allows reactions to be performed at high temperatures, such as at the solvent&#39;s boiling point, without losing the solvent to evaporation.</p>
	<p>Refluxing is achieved with a special piece of glassware called a condenser, which is attached directly to your flask. The condenser is cooled with water flowing through the outer chamber. As vapor rises through the condenser, it loses heat to the cool walls, condenses, and drips back into the flask.</p>
	<p>Refluxing is usually performed in a round-bottom flask. These flasks must be heated in a heating bath or with specialized equipment, but they provide more even heating than an Erlenmeyer flask or beaker as a result. Water baths are typically used for experiments performed below 80 &#8211; 100 &#176;C.</p>
	<ul class="lab-items">
		<li data-sub-note-item="2-4">
		<div class="lab-step">Set up the glassware and equipment for reflux. Place a lab jack by your available lab stand and set a stirring hotplate on top of it. Clamp a 50-mL round-bottom flask at least 12 cm above the hotplate.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Bring a 50-mL graduated cylinder to the solvent hood and measure 25 mL of THF. If you pour too much, label a small beaker &#8216;organic waste&#8217; and pipette the excess into that. Remember to cap the bottle when you&#39;re done.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">Carefully pour the THF into the round-bottom flask, clean up any spills with a lab wipe or paper towel, and add a small oblong stir bar to the flask.</div>
		</li>
		<li data-sub-note-item="2-7">
		<div class="lab-step">Position a medium clamp ~20 cm above the flask. Obtain a condenser and apply vacuum grease to the lower ground-glass joint.</div>
		</li>
		<li data-sub-note-item="2-8">
		<div class="lab-step">Fit the condenser into the flask and rotate them in opposite directions until the vacuum grease is evenly spread between the two ground-glass surfaces.</div>
		</li>
		<li data-sub-note-item="2-9">
		<div class="lab-step">Clamp the condenser in place and use a lab wipe to remove excess grease from the connection between the two pieces of glassware.</div>
		</li>
		<li data-sub-note-item="2-10">
		<div class="lab-step">Attach rubber tubing to each of the ports on the condenser. Place the free end of the tubing connected to the top port, which is the outlet, in the drain. Connect the free end of the tubing from the bottom port, which is the inlet, to the waterline.</div>
		</li>
		<li data-sub-note-item="2-11">
		<div class="lab-step">Fill a 250-mL beaker with ~200 mL of tap water and place this water bath on the hotplate. Use the lab jack to raise the bath until the water level is about 2/3 of the way up the spherical part of the flask. This will ensure the THF heats evenly.</div>
		</li>
		<li data-sub-note-item="2-12">
		<div class="lab-step">Secure a thermometer (range 0 &#8211; 100 &#176;C) in the bath using the thermometer clamp.</div>
		</li>
		<li data-sub-note-item="2-13">
		<div class="lab-step">Slowly open the water tap, watch the condenser for leaks as it fills, and confirm that the water is flowing into the drain.</div>
		</li>
		<li data-sub-note-item="2-14">
		<div class="lab-step">Slowly turn up the magnetic stirrer until the THF is stirring well. If the stir bar bounces around, turn down the stir motor and try again more slowly.</div>
		</li>
		<li data-sub-note-item="2-15">
		<div class="lab-step">Start heating the water bath to about 70 &#176;C until the THF starts to boil. <strong>Note: </strong>You&#39;ll see vapor condensing in the lower part of the condenser).</div>
		</li>
		<li data-sub-note-item="2-16">
		<div class="lab-step">Monitor the refluxing THF for 10 min. <strong>Note:</strong> Turn down the heat if the bath goes above 70 &#176;C or if vapor leaves the condenser.</div>
		</li>
		<li data-sub-note-item="2-17">
		<div class="lab-step">After 10 min, remove the thermometer and turn off the heat and the stir motor. Carefully lower the lab jack until the flask is clear of the water bath. Wait at least 10 more min for the setup to cool, then unplug and remove the hotplate.</div>
		</li>
		<li data-sub-note-item="2-18">
		<div class="lab-step">Turn off the water tap, unclamp the condenser, and carefully detach it from the flask. Tilt the condenser until most of the water has flowed through the outlet tubing into the drain. Then, disconnect the inlet tubing from the condenser and let the remaining water flow into the drain. Do the same for the outlet tubing.</div>
		</li>
		<li data-sub-note-item="2-19">
		<div class="lab-step">Use lab wipes to remove the vacuum grease from the condenser and the flask, then retrieve the stir bar from the flask.</div>
		</li>
		<li data-sub-note-item="2-20">
		<div class="lab-step">Bring the flask to the waste hood and empty it into the non-halogenated organic waste container. Pour any excess HCl or THF into the acid and organic wastes, respectively. Empty the ice and water baths into the sink and rinse the beakers with tap water.</div>
		</li>
		<li data-sub-note-item="2-21">
		<div class="lab-step">Clean most of your other glassware while the benzoic acid from earlier finishes drying according to your lab&#8217;s standard practices. Usually, you&#39;ll rinse your glassware both with an organic solvent, like acetone, and with detergent and deionized water. <strong>Note:</strong> Your lab may have specific procedures for glassware used with acids. If so, follow that procedure to clean the graduated cylinder used with HCl and your acid waste beaker, if applicable.</div>
		</li>
		<li data-sub-note-item="2-22">
		<div class="lab-step">Remove the reusable pipette bulbs and dispose of your pipettes in the glass waste container. Throw out used lab wipes and paper towels in the lab trash.</div>
		</li>
		<li data-sub-note-item="2-23">
		<div class="lab-step">Check on your benzoic acid. If it is dry, turn off the vacuum and break the vacuum seal by disconnecting the tubing from the filter flask. Gently place the funnel in it 250-mL beaker and bring it and your lab notebook to the balance.</div>
		</li>
		<li data-sub-note-item="2-24">
		<div class="lab-step">Tare a weighing boat and use a clean spatula to transfer the product to the weighing boat. Record the mass of your product in your lab notebook.</div>
		</li>
		<li data-sub-note-item="2-25">
		<div class="lab-step">Then, put the product in the lab trash and wipe off the spatula. Dispose of the filtrate in the aqueous waste container.</div>
		</li>
		<li data-sub-note-item="2-26">
		<div class="lab-step">Clean the rest of your glassware, throw out the filter paper and other waste in the lab trash, and put away your lab equipment. Lastly, clean the floor of your fume hood with a damp paper towel.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="3" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="3-1">
		<div class="lab-step">Calculate the reaction yield for the protonation of sodium benzoate. Identify the reagent that the reaction runs out of first, which is called the limiting reagent.</div>
		</li>
		<li data-sub-note-item="3-2">
		<div class="lab-step">Calculate the number of moles of sodium benzoate and HCl that you used. <strong>Note:</strong> You used about 0.014 moles of sodium benzoate and 0.015 moles of HCl. Thus, the maximum yield of benzoic acid is equal to the starting amount of sodium benzoate in moles.</div>
		</li>
		<li data-sub-note-item="3-3">
		<div class="lab-step">Convert the mass of your benzoic acid to moles, divide that by the moles of sodium benzoate that you used, and multiply it by 100 to get the percent yield. <strong>Note:</strong> The recovered yield for this reaction is usually between 80% and 98% because a small amount of benzoic acid stays in solution. If the yield is above 100%, then it&#39;s likely that your product was still wet when you weighed it. Impurities, unreacted compounds, and products of side reactions can also affect the accuracy of yield calculations.</div>
		</li>
	</ul>
	</li>
</ol>

기본 유기 화학 기법

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Synthesis of Benzoic AcidExpand
	In this lab, you&#39;ll ...

Recrystallization

<p>Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Recrystallization of Acetanilide<button class="expand">Expand</button>
	<p>In this part of the lab, you&#39;ll purify acetanilide by recrystallization from an aqueous solution. Acetanilide is moderately soluble in boiling water, but it&#39;s much less soluble in room temperature and cold water. Aniline, a potential impurity, is much more soluble in room temperature water. Thus, you&#39;ll first make a saturated solution of acetanilide in boiling water. Then, you&#39;ll slowly cool the solution to room temperature.</p>
	<p>As the acetanilide&#39;s solubility decreases, it will slowly form flat colorless or white crystals. Water-soluble impurities will remain in solution. You will then cool the solution to further decrease the solubility of acetanilide. Finally, you&#39;ll recover the crystals with vacuum filtration and measure the melting point of your crystals.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-3">
		<div class="lab-step">Before you start the lab, put on a lab coat, safety glasses, and nitrile gloves.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">To begin, bring a 125-mL Erlenmeyer flask and your lab notebook to the analytical balance to obtain your acetanilide.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Measure 2 g of acetanilide in a tared weighing boat and record the precise mass in your lab notebook. Add the acetanilide to the flask and bring it back to your fume hood.
		<h4><strong>Table 1: Recrystallization of acetanilide</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td><strong>Compound</strong></td>
					<td><strong>Mass (g) </strong></td>
					<td><strong>Melting point (&#176;C) </strong></td>
				</tr>
				<tr>
					<td>Acetanilide</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Seed crystal (if used)</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Recrystallized acetanilide<br />
					(<em>subtract seed crystal if used</em>)</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td><strong>Percent recovery</strong></td>
					<td></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/58/Table_1._Recrystallization_of_acetanilide.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Then, measure 30 mL of deionized water and carefully pour it into the flask of acetanilide.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Place the flask on a stirring hotplate, add a stir bar, and set the hotplate to medium heat and stirring. Let the mixture boil for 4 &#8211; 5 min to dissolve the acetanilide.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">If you see solid acetanilide after the solution has boiled for 5 min, measure another 10 mL of deionized water. Use a Pasteur pipette to add water dropwise until either the solid dissolves or you&#39;ve added all 10 mL.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Let the solution boil for at least a minute after each milliliter before adding more water.<strong> Note:</strong> It&#39;s important to add water slowly so that you don&#39;t cool the solution too much or add more water than you need.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">If you still see some solid after that, those are impurities that you must remove by hot filtration. If you do not see solid, continue the lab at step 14.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">To perform hot filtration, place about 15 mL of deionized water and one or two boiling chips in a 50-mL beaker and start heating it on a hotplate.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Clamp another 125-mL Erlenmeyer flask on a hotplate and place a wide stem or stemless glass funnel in the flask. Fold a large piece of circular filter paper in quarters, place it point down in the funnel, and open it into a cone.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Once the water boils, use a pipette to wet the filter paper with hot water. Then, use tongs to pick up the flask of acetanilide solution and pour the hot liquid into the funnel, being careful not to let it overflow. <strong>Note:</strong> If the stir bar falls into the funnel, retrieve it with tweezers and rinse it with hot water.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">Then, rinse the inside of the first flask with a few milliliters of hot water, pour the contents into the funnel, and dissolve any crystals that form with hot water.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Once the funnel is empty, use tongs to move it to the first flask. Carefully unclamp the second flask. You can now continue with the lab as usual.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Once there is no visible solid in your hot acetanilide solution, turn off the heat and stir motor and use tongs to place the flask on the floor of the hood.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Leave the solution undisturbed as it cools to room temperature, which usually takes at least 15 min. Moving or shaking the flask will make it harder for crystals to form.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">While you wait, place a small amount of the starting acetanilide material in a weighing boat and bring it to the melting point apparatus.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">Pack a capillary tube with the acetanilide and measure and record its melting point.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Once the solution cools, look for crystals without moving the flask too much. If you don&#39;t see any, use a glass rod to gently scratch the inside of the flask under the solution. It&#39;s easier for crystals to start to form on scratched or rough surfaces.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">If crystals still haven&#39;t formed after 10 more min, ask your instructor for a seed crystal of high purity acetanilide. Measure and record the mass of the seed crystal, and then drop it into the room temperature acetanilide solution. Crystal growth will then occur on the seed crystal.</div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">Once you see several crystals in the flask, prepare two ice baths in 600-mL beakers. One ice bath should nearly fill the beaker, and the other should occupy about half of the beaker.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Measure 5 mL of deionized water and place it in the full ice bath. Confirm that the flask is cool to the touch and that several crystals have formed before gently placing it in the half-full ice bath. Leave the flask undisturbed to improve crystal growth.</div>
		</li>
		<li data-sub-note-item="1-24">
		<div class="lab-step">Check the crystal growth progress every 15 min. Once it looks like most of your acetanilide has crystallized, or you don&#39;t see much crystal growth over a 15-min period, set up for a vacuum filtration using a 125- or 250-mL filter flask.</div>
		</li>
		<li data-sub-note-item="1-25">
		<div class="lab-step">Wet the filter paper with 1 mL of ice-cold water. Then, start the vacuum and pour the contents of the flask into the B&#252;chner funnel of the vacuum filtration setup.</div>
		</li>
		<li data-sub-note-item="1-26">
		<div class="lab-step">Scrape crystals from the flask into the funnel using a glass rod or flexible spatula and rinse the remaining crystals into the funnel with about 1 mL of cold deionized water.</div>
		</li>
		<li data-sub-note-item="1-27">
		<div class="lab-step">Then, stop the vacuum, break the seal, and pour the rest of the cold deionized water into the funnel. Gently stir the crystals with the glass rod for a few seconds to wash them, being careful not to tear the filter paper.</div>
		</li>
		<li data-sub-note-item="1-28">
		<div class="lab-step">Turn on the vacuum to drain the funnel. Then, stop the vacuum, break the seal, and empty the filtrate into a waste beaker. Turn the vacuum back on, and leave the washed crystals in the funnel while the vacuum pump pulls air through them until they are dry, which usually takes about half an hour. You&#39;ll start working on your next recrystallization while you wait.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Recrystallization of <em>trans</em>-Cinnamic Acid<button class="expand">Expand</button>
	<p>In the second half of the lab, you&#39;ll recrystallize <em>trans</em>-cinnamic acid, which we&#39;ll just call cinnamic acid. Cinnamic acid is soluble in ethanol and nearly insoluble in water. So, you&#39;ll use a mixture of 95% ethanol and 5% water so that cinnamic acid is still soluble at high temperatures but less soluble at low temperatures.</p>
	<ul class="lab-items">
		<li data-sub-note-item="2-2">
		<div class="lab-step">To get started, fill a 5- or 10-mL graduated cylinder with deionized water and bring it to your hood.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">Then, weigh 0.5 g of cinnamic acid, record its mass, and place it in a 25-mL Erlenmeyer flask.
		<h4><strong>Table 2: Recrystallization of<em> trans</em>-Cinnamic acid</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td><strong>Compound</strong></td>
					<td><strong>Mass (g) </strong></td>
					<td><strong>Melting point (&#176;C) </strong></td>
				</tr>
				<tr>
					<td><em>trans</em>-Cinnamic acid</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Seed crystal (if used)</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Recrystallized<em> trans</em>-cinnamic acid<br />
					<em>(subtract seed crystal if used)</em></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td><strong>Percent recovery</strong></td>
					<td></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://jove.unicartagenaproxy.elogim.com/CDNSource/lm/labs/58/Table_2._Recrystallization_of_trans-Cinnamic_acid.xlsx" target="_blank">Click Here to download Table 2</a></div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">Next, obtain 4 mL of 95% ethanol, and pour it into the flask containing cinnamic acid. Place the flask on a hotplate set to medium heat and stir the solution with a glass rod until the cinnamic acid dissolves, which usually takes 7 &#8211; 10 min.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Then, turn off the heat and use a Pasteur pipette to add 5 drops of deionized water to the solution. This reduces cinnamic acid solubility. <strong>Note:</strong> If you don&#39;t see precipitation, add up to 5 more drops of water one by one. Stop adding water if you see solids starting to form.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">Then, remove the flask from the hotplate and let it cool to room temperature undisturbed.</div>
		</li>
		<li data-sub-note-item="2-7">
		<div class="lab-step">While you wait, get a small amount of the starting cinnamic acid and measure its melting point.</div>
		</li>
		<li data-sub-note-item="2-8">
		<div class="lab-step">Once the flask has cooled to room temperature, inspect it for crystals. If you don&#39;t see any, gently scratch the inside of the flask under the solution with the glass rod and wait for 10 min. <strong>Note:</strong> If that still doesn&#39;t work, get a seed crystal of cinnamic acid from your instructor. Remember to weigh the seed crystal and record its mass before you add it to your solution.</div>
		</li>
		<li data-sub-note-item="2-9">
		<div class="lab-step">Once the flask is cool to the touch and contains several crystals, remake the ice baths with one ice bath shallow enough that the 25-mL flask will not be completely submerged.</div>
		</li>
		<li data-sub-note-item="2-10">
		<div class="lab-step">Refill the graduated cylinder with deionized water. Place the flask of cinnamic acid crystals in the shallow ice bath and the water-filled graduated cylinder in the other ice bath. Let the crystals grow for at least 15 min.</div>
		</li>
		<li data-sub-note-item="2-11">
		<div class="lab-step">Your acetanilide crystals should be dry by now, so measure their mass and melting point while you wait for your cinnamic acid to finish crystallizing. Turn off the vacuum and break the vacuum seal.</div>
		</li>
		<li data-sub-note-item="2-12">
		<div class="lab-step">Gently place the B&#252;chner funnel in a clean beaker and bring it to the balance. Measure and record the mass of your pure acetanilide crystals. Remember to subtract the mass of the seed crystal if you used one.</div>
		</li>
		<li data-sub-note-item="2-13">
		<div class="lab-step">Then, bring your crystals to the melting point apparatus and measure and record the melting point.</div>
		</li>
		<li data-sub-note-item="2-14">
		<div class="lab-step">Now, place a clean, dry B&#252;chner funnel with a new piece of filter paper in the filter flask and check on your cinnamic acid. Once it looks like most of the cinnamic acid has crystallized, wet the filter paper with cold deionized water.</div>
		</li>
		<li data-sub-note-item="2-15">
		<div class="lab-step">Start the vacuum and pour the contents of the cinnamic acid flask into the funnel. Scrape the remaining crystals out of the flask with the glass rod and rinse the flask with about 1 mL of cold water.</div>
		</li>
		<li data-sub-note-item="2-16">
		<div class="lab-step">Now, turn off the vacuum, break the seal, and pour the rest of the cold water into the funnel. Gently stir the crystals with the glass rod to wash them, being careful not to damage the filter paper.</div>
		</li>
		<li data-sub-note-item="2-17">
		<div class="lab-step">Turn on the vacuum to drain the funnel. Leave the vacuum running until the cinnamic crystals are dry.</div>
		</li>
		<li data-sub-note-item="2-18">
		<div class="lab-step">Place the B&#252;chner funnel in a beaker and bring it to the balance. Measure and record the mass of your pure cinnamic acid crystals. Remember to subtract the mass of the seed crystal if you used one. Then, measure the melting point of your recrystallized cinnamic acid.</div>
		</li>
		<li data-sub-note-item="2-19">
		<div class="lab-step">Now, dispose of your acetanilide and cinnamic acid in the designated solid waste container. Flush the filtrate down the drain with running water and pour leftover ice and water into the sink.</div>
		</li>
		<li data-sub-note-item="2-20">
		<div class="lab-step">Clean your glassware using your usual methods and put away your other lab equipment.</div>
		</li>
		<li data-sub-note-item="2-21">
		<div class="lab-step">Lastly, discard your used pipettes in the glass waste and throw out used filter paper and other trash in the lab trash container.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="3" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="3-1">
		<div class="lab-step">First, calculate the percent recovery for each compound. We expect that some of each compound stayed in solution, so these percentages will be below the reported purity of your starting material.</div>
		</li>
		<li data-sub-note-item="3-2">
		<div class="lab-step">Now, look at the differences in melting points between the starting material and the crystals. For each compound, the less pure starting material has a lower melting point and a broader range than the recrystallized compound.</div>
		</li>
		<li data-sub-note-item="3-3">
		<div class="lab-step">Lastly, compare your results to the literature values. The melting point of acetanilide is 114 &#176;C, and the melting point of <em>trans</em>-cinnamic acid is 133 &#176;C. The melting points of your crystals should span 1 &#8211; 2 &#176;C and should be at or just below those values.</div>
		</li>
	</ul>
	</li>
</ol>

Recrystallization of Acetanilide and trans-Cinnamic Acid - Procedure

재결정화

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Recrystallization of AcetanilideExpand
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