The authors would like to acknowledge support from the Government of Canada's interdepartmental Program of Energy Research and Development, PERD 113, Petroleum Conversion for Cleaner Air. N.E.H would like to acknowledge her Natural Sciences and Engineering Research Council of Canada Visiting Fellowship.

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The authors have nothing to disclose.

כדי להשיג מדידה אופטימלית של H 2 S, שיטה זו מעסיקה מתג דיקנים, backflushing וגלאי chemiluminescence גופרית (SCD). טור dimethylpolysiloxane משמש כעמודת GC הממד הראשונה, ומשמש ללעכב את התנועה של פחמימנים כבדים הווה במדגם, כך שהם לא לזהם את טור העלילה. השפעה זו מוגברת על ידי מגניב (50 מעלות צלזיוס)...

ניתוח מדויק של נפט גולמי הוא חיוני לתעשיית הנפט והגז, כמו תקנות בריאות ובטיחות וכלכלה הן פונקציות של איכות שמן. על מנת להגן על מובילים של דגימות גולמיים, יש צורך לקבוע את המאפיינים של דגימות גולמיים לפתח תקנות בטיחות ייושם במקרה של שחרור או לשפוך. בפרט, כימות של מימן גופרתי (H 2 S) היא חשובה, בשל רעילותו הגבוהה בשלב הגז; חשיפות נמוכות כמו 100 עמודים לדקה יכולה להיות קטלני (http://www.cdc.gov/niosh/idlh/7783064.html) 1,2. H 2 S מומס בדגימות גולמיים נחשב בדרך כלל להיות מאכל 3,4, ותוכל לבטל את הזרזים המשמשים לטיפול השמן 5-7. ההסרה של H 2 S מזרמים נפט הגולמי היא אידיאלית, אבל ללא שיטה למדידה מומסת H 2 S, זה קשה להעריך את ההצלחה של טיפולים להסרת. מסיבות אלה, פרוטוקול זה פותח כדי למדוד dissolved H 2 S בדגימות נפט גולמי כבדות כגון נפט גולמי חולות נפט קנדיות. מספר השיטות סטנדרטיים קיימים לכימות של H 2 S בדגימות נפט או דלק מבוסס קלות יותר, אבל אף אחד אומתו לשימוש עם הנפט הגולמי הכבד שחולץ נפוץ מחולות הנפט הקנדיות. H 2 S וmercaptans נקבעים באמצעות טכניקת טיטרציה על ידי מוצרי יוניברסל שמן (UOP) שיטה 163 8, אך שיטה זו סובלת מהטית משתמש פרשנות שנובעת מקריאה ידנית של עקומות טיטרציה. מכון נפט השיטה (IP) 570 משתמש H 2 S מנתח מיוחד שמחמם דגימות מזוט 9, ונהנה מפשטות ואת הטלטלות, אבל חסר דיוק עם דגימות כבדות 10. האגודה האמריקנית לבדיקות וחומרים (ASTM) D5623 השיטה משתמשת גז כרומטוגרפיה (GC) עם קירור קריוגני וזיהוי סלקטיבית גופרית למדוד H 2 S בנוזלי נפט אור11,12. תקן זה יכול להיות שיפור להשתמש הפרדת סביבה וגם להיות מיושם על נפט גולמי כבד, ולכן הוא שימש כבסיס לפרוטוקול נדון במסמך זה. GC הוא טכניקה המשמשת במידה רבה לניתוח דגימות נפט. דוגמאות מתאדים בכניסה חמה, והפרדות להתרחש בשלב הגז. הפרדת שלב הגז הופכת אידיאלית GC לניתוח של H 2 S, כפי שהוא שוחרר בקלות מהמדגם הנוזלי במהלך חימום בכניסה. ניתן ליצור שיטות GC ומותאמות למדגמים שונים, בהתאם לתוכניות הטמפרטורה משמשות, מיושמות עמודות, והשימוש בכרומטוגרפיה רב ממדית 13-15. יש כבר מספר ההתפתחויות האחרונות למדידת H 2 S באמצעות GC. ואונג et al. הפגין H 2 S ומדידת מתחם גופרית אור אחרת באור ותזקיקי ביניים באמצעות GC רב-ממדי ומיתוג דיקנים, אבל השיטה יש לאעדיין הוחל על נפט גולמי כבד 16. די Sanzo et al. H גם לכמת 2 S בבנזין באמצעות GC, אבל זה גם לא נעשה שימוש בנפט גולמי כבד, ודורש תת-סביבה קירור 17. השיטה המוצגת כאן ממחישה זמן ניכר חיסכון על פני השיטות הקודמות אלה, עם זמן ניתוח הושלם של 5 דקות, לעומת 10 דקות (ואונג) ו -40 דקות (Di Sanzo). למרבה הצער, היישום של שיטות אלה במעבדה שלנו כדי להשוות את הדיוק לא היה אפשרי בשל מגבלות ציוד והזמן. GC הרב ממדי מאפשר למשתמש לנצל את הסלקטיביות של שתי עמודות, ולא בעמודה אחת. בGC הקונבנציונלי, הפרדה מתרחשת בעמודה אחת. במקרה של GC הרב ממדי, המדגם מופרד על שתי עמודות שונות, שיפור ההפרדה וסלקטיביות. מתג הדיקנים הוא מכשיר אחד משמש להעסיק תצורת טור דו-ממדית. המתג משתמש שסתום חיצוני לחמורזרימת גז CT מכניסה במתג לאחת משתי יציאות לשקע 18-20. שפכים מהעמודה הראשונה יכולים להיות מופנה לשני כיוונים; במקרה זה, גזי גופרית אור הם &quot;חתך לב&quot; 21 מההפרדה הראשונה לצינור פתוח שכבה נקבובית טור (חלקה) להפרדה משנית, אשר הוכחה להיות מעולה להפרדה של H 2 S מגזי גופרית אור אחרים (Http://www.chem.agilent.com/cag/cabu/pdf/gaspro.pdf) 22-24. גלאי chemiluminescence הגופרית משמש לזיהוי, מתן סלקטיביות לתרכובות גופרית וביטול הפרעה אפשרית מכל גזי אור אחרים שייתכן שהועברו לטור החלקה בחתך הלב. פחמימנים ממדגם הנפט הגולמי נשמרים על עמודת הממד הראשונה ויוסרו במהלך הליך backflush; זה מגן על עמודת עלילה מכל זיהום 25-27. גישה זו גם יושמה בהצלחה לאנאליתיסיס של מעכבי חמצון בשמני שנאי 28. במסמך זה, שיטת GC דו ממדים מועסקת לניתוח והכימות של H 2 S מומס בדגימות נפט גולמי כבדות. השיטה מוצגת להיות ישים על פני טווח רחב של H 2 S ריכוזים, ויכולה לשמש גם למדידת H 2 S בדגימות שלב גז.

<table><tbody><tr><td>Deans switch</td><td>Agilent</td><td>G2855A</td><td>Or equivalent flow switching device</td></tr><tr><td>Restrictor tubing&amp;nbsp;</td><td>Agilent</td><td>160-2615-10</td><td>Fused silica, deactivated, 180 &amp;micro;m</td></tr><tr><td>HP-PONA column</td><td>Agilent</td><td>19091S-001</td><td></td></tr><tr><td>GasPro column</td><td>Agilent</td><td>113-4332</td><td></td></tr><tr><td>Sulfur chemiluminescence detector, 355</td><td>Agilent/Sievers</td><td>G6603A</td><td></td></tr><tr><td>H&lt;sub&gt;2&lt;/sub&gt;S calibration standard, in He</td><td>Air Liquide</td><td>Custom order</td><td>211 ppm H&lt;sub&gt;2&lt;/sub&gt;S</td></tr><tr><td>CS&lt;sub&gt;2&lt;/sub&gt;</td><td>Fisher Scientific</td><td>C184-500</td><td></td></tr><tr><td>Toluene, HPLC grade</td><td>Fisher Scientific</td><td>T290-4</td><td></td></tr><tr><td>Gas bag, 2 L</td><td>Calibrated Instruments, Inc.</td><td>GSB-P/2</td><td>Twist on/off nozzle</td></tr><tr><td>250 &amp;micro;l gas tight syringe</td><td>Hamilton</td><td>81130</td><td></td></tr><tr><td>500 ml amber glass bottle</td><td>Scientific Specialties</td><td>N73616</td><td></td></tr><tr><td>Open top screw caps</td><td>Scientific Specialties</td><td>169628</td><td></td></tr><tr><td>Tegrabond disc for screw caps</td><td>Chromatographic Specialties</td><td>C889125C</td><td>25 mm, 10/90 MIL</td></tr><tr><td>1 ml gas tight syringe</td><td>Hamilton</td><td>81330</td><td></td></tr><tr><td>2.5% H&lt;sub&gt;2&lt;/sub&gt;S in He gas standard</td><td>Air Liquide</td><td>Custom order</td><td></td></tr></tbody></table>

measurement of h2s in crude oil and crude oil headspace using multidimensional gas chromatography, deans switching and sulfur-selective detection

שיטה לניתוח מימן גופרתי מומס בדגימות נפט גולמיים מודגמת באמצעות גז כרומטוגרפיה. על מנת למנוע ביעילות הפרעות, משמשת שתי תצורת עמודה ממדית, עם מתג דיקנים המועסקים להעביר מימן גופרתי מהראשון לעמודה השנייה (לב-חיתוך). דגימות גולמי נוזליים מופרדות ראשונה בטור dimethylpolysiloxane, וגזי אור הם ועוד מופרד על עמודת צינור פתוח שכבה נקבובית ערובה (חלקה) כי הוא מסוגל להפריד מימן גופרתי ממיני גופרית אור אחרים-לחתוך לב. מימן גופרתי לאחר מכן זוהה עם גלאי chemiluminescence גופרית, הוספת שכבה נוספת של הסלקטיביות. בעקבות הפרדה וזיהוי של מימן גופרתי, מערכת backflushed להסיר את פחמימנים רותחים גבוהים הנוכחיים בדגימות גולמי וכדי לשמור על שלמות chromatographic. מימן הגופרתי מומס כבר לכמת בדגימות נוזל 1.1-500 עמ &#39;בערב, מפגין תחולה רחבה למגוון של דוגמאות. השיטה גם יושמה בהצלחה לניתוח של דגימות גז משקיות אמיץ נפט גולמי וגז תהליך, עם מדידה מ0.7 ל9,700 מימן גופרתי עמודים לדקה.

על מנת לקבל כימות אמין של H 2 S לדגימות שני נוזל וגז, כיול נכון הוא הכרחי. לזריקות כיול וזריקות מדגם, שיא H 2 S לא צריך להיות חופף עם פסגות שכנות וצריך אזור שיא לשחזור. איור 3 מראה הזרקה של מדגם גז שבו הגז הוא מרוכז מדי לשיטה זו. נמצא כי ריכוזי גז של יותר מ...

Watch this Scientific Journal Video about Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection at JoVE.com

Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection

A multidimensional gas chromatography method for the analysis of dissolved hydrogen sulfide in liquid crude oil samples is presented. A Deans switch is used to heart-cut light sulfur gases for separation on a secondary column and detection on a sulfur chemiluminescence detector.

מדידה של H<sub&gt; 2</sub&gt; S בנפט גולמי ונפט הגולמי Headspace שימוש רב מימדי גז כרומטוגרפיה, דיקני מיתוג ואיתור גופרית סלקטיבי

A method for the analysis of dissolved hydrogen sulfide in crude oil samples is demonstrated using gas chromatography. In order to effectively eliminate ...

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Universidad de Cartagena UDEC

Research

JoVE Journal

Environment

Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection

19.1K Views.  Natural Resources Canada. A multidimensional gas chromatography method for the analysis of dissolved hydrogen sulfide in liquid crude oil samples is presented. A Deans switch is used to heart-cut light sulfur gases for separation on a secondary column and detection on a sulfur chemiluminescence detector. 

Video: Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection

Characterizing Bacterial Volatiles using Secondary Electrospray Ionization Mass Spectrometry (SESI-MS)

Secondary electrospray ionization mass spectrometry (SESI-MS) is a method developed for the rapid detection of volatile compounds, without the need for sample pretreatment. The method was first described by Fenn and colleagues1 and has been applied to the detection of illicit drugs2 and explosives3-4, the characterization of skin volatiles5, and the analysis of breath6-7.
SESI ionization occurs by proton transfer reactions between the electrospray solution and the volatile analyte, and is therefore suitable for the analysis of hetero-organic molecules, just as in traditional electrospray ionization (ESI). However, unlike standard ESI, the proton transfer process of SESI occurs in the vapor phase rather than in solution (Fig. 1), and therefore SESI is best suited for detecting organic volatiles and aerosols.
We are expanding the use of SESI-MS to the detection of bacterial volatiles as a method for bacterial identification and characterization8. We have demonstrated that SESI-MS volatile fingerprinting, combined with a statistical analysis method, can be used to differentiate bacterial genera, species, and mixed cultures in a variety of growth media.8 Here we provide the steps for obtaining bacterial volatile fingerprints using SESI-MS, including the instrumental parameters that should be optimized to ensure robust bacterial identification and characterization.

Characterizing Bacterial Volatiles using Secondary Electrospray Ionization Mass Spectrometry SESI-MS

Secondary electrospray ionization mass spectrometry (SESI-MS) enables the detection of volatile organic compounds (VOCs) without the need for any sample pretreatment. This protocol provides instructions for the rapid (within minutes) characterization of bacterial VOCs using SESI-MS.

נדיפים חיידקית משנית אפיון באמצעות Ionization electrospray ספקטרומטריית מסה (SESI-MS)

Secondary electrospray ionization mass spectrometry (SESI-MS) is a method developed for the rapid detection of volatile compounds, without the need for ...

Bioengineering

Quantitative Detection of Trace Explosive Vapors by Programmed Temperature Desorption Gas Chromatography-Electron Capture Detector

The direct liquid deposition of solution standards onto sorbent-filled thermal desorption tubes is used for the quantitative analysis of trace explosive vapor samples. The direct liquid deposition method yields a higher fidelity between the analysis of vapor samples and the analysis of solution standards than using separate injection methods for vapors and solutions, i.e., samples collected on vapor collection tubes and standards prepared in solution vials. Additionally, the method can account for instrumentation losses, which makes it ideal for minimizing variability and quantitative trace chemical detection. Gas chromatography with an electron capture detector is an instrumentation configuration sensitive to nitro-energetics, such as TNT and RDX, due to their relatively high electron affinity. However, vapor quantitation of these compounds is difficult without viable vapor standards. Thus, we eliminate the requirement for vapor standards by combining the sensitivity of the instrumentation with a direct liquid deposition protocol to analyze trace explosive vapor samples.

Trace explosive vapors of TNT and RDX collected on sorbent-filled thermal desorption tubes were analyzed using a programmed temperature desorption system coupled to GC with an electron capture detector. The instrumental analysis is combined with direct liquid deposition method to reduce sample variability and account for instrumentation drift and losses.

כמותי איתור של אדי נפץ Trace ידי טמפרטורת מתוכנת Desorption גלאי גז לכידת כרומטוגרפיה-אלקטרונים

The direct liquid deposition of solution standards onto sorbent-filled thermal desorption tubes is used for the quantitative analysis of trace explosive ...

Chemistry

Preparation of Authigenic Pyrite from Methane-bearing Sediments for In Situ Sulfur Isotope Analysis Using SIMS

Different sulfur isotope compositions of authigenic pyrite typically result from the sulfate-driven anaerobic oxidation of methane (SO4-AOM) and organiclastic sulfate reduction (OSR) in marine sediments. However, unravelling the complex pyritization sequence is a challenge because of the coexistence of different sequentially formed pyrite phases. This manuscript describes a sample preparation procedure that enables the use of secondary ion mass spectroscopy (SIMS) to obtain in situ &#948;34S values of various pyrite generations. This allows researchers to constrain how SO4-AOM affects pyritization in methane-bearing sediments. SIMS analysis revealed an extreme range in &#948;34S values, spanning from -41.6 to +114.8&#8240;, which is much wider than the range of &#948;34S values obtained by the traditional bulk sulfur isotope analysis of the same samples. Pyrite in the shallow sediment mainly consists of 34S-depleted framboids, suggesting early diagenetic formation by OSR. Deeper in the sediment, more pyrite occurs as overgrowths and euhedral crystals, which display much higher SIMS &#948;34S values than the framboids. Such 34S-enriched pyrite is related to enhanced SO4-AOM at the sulfate-methane transition zone, postdating OSR. High-resolution in situ SIMS sulfur isotope analyses allow for the reconstruction of the pyritization processes, which cannot be resolved by bulk sulfur isotope analysis.

Preparation of Authigenic Pyrite from Methane-bearing Sediments for In Situ Sulfur Isotope Analysis Using SIMS

Analyses of the sulfur isotopic composition (&#948;34S) of pyrite from methane-bearing sediments have typically focused on bulk samples. Here, we applied secondary ion mass spectroscopy to analyze the &#948;34S values of various pyrite generations to understand the diagenetic history of pyritization.

הכנה של פיריט Authigenic ממשקעים מתאן מניבי בחיי עיר גופרית איזוטופ ניתוח באמצעות סימס

Different sulfur isotope compositions of authigenic pyrite typically result from the sulfate-driven anaerobic oxidation of methane (SO4-AOM) and ...

On-line Analysis of Nitrogen Containing Compounds in Complex Hydrocarbon Matrixes

The shift to heavy crude oils and the use of alternative fossil resources such as shale oil are a challenge for the petrochemical industry. The composition of heavy crude oils and shale oils varies substantially depending on the origin of the mixture. In particular they contain an increased amount of nitrogen containing compounds compared to the conventionally used sweet crude oils. As nitrogen compounds have an influence on the operation of thermal processes occurring in coker units and steam crackers, and as some species are considered as environmentally hazardous, a detailed analysis of the reactions involving nitrogen containing compounds under pyrolysis conditions provides valuable information. Therefore a novel method has been developed and validated with a feedstock containing a high nitrogen content, i.e., a shale oil. First, the feed was characterized offline by comprehensive two-dimensional gas chromatography (GC &#215; GC) coupled with a nitrogen chemiluminescence detector (NCD). In a second step the on-line analysis method was developed and tested on a steam cracking pilot plant by feeding pyridine dissolved in heptane. The former being a representative compound for one of the most abundant classes of compounds present in shale oil. The composition of the reactor effluent was determined via an in-house developed automated sampling system followed by immediate injection of the sample on a GC &#215; GC coupled with a time-of-flight mass spectrometer (TOF-MS), flame ionization detector (FID) and NCD. A novel method for quantitative analysis of nitrogen containing compounds using NCD and 2-chloropyridine as an internal standard has been developed and demonstrated.

A method combining comprehensive two-dimensional gas chromatography with nitrogen chemiluminescence detection has been developed and applied to on-line analysis of nitrogen containing compounds in a complex hydrocarbon matrix.

ניתוח אונליין של חנקן המכיל תרכובות ב מטריצות פחמימן Complex

The shift to heavy crude oils and the use of alternative fossil resources such as shale oil are a challenge for the petrochemical industry. The ...

Rapid Collection of Floral Fragrance Volatiles using a Headspace Volatile Collection Technique for GC-MS Thermal Desorption Sampling

Fragrances of many flower families have been sampled and the volatiles analyzed. Knowing the compounds that make up the fragrances can be an important step to conservation of flowers that are threatened or endangered. Because floral fragrance is critical for attracting pollinators, this method could be used to better understand or even enhance pollination. We present a protocol using a portable charcoal air filter and vacuum to collect floral fragrance volatiles, which are then analyzed by a GC-MS. By using this method, fragrance volatiles can be sampled using a non-destructive method with a machine that is easily transported. This methodology uses a rapid sampling procedure, cutting sampling time down from 2-3 hours to approximately 10 minutes. Using GC-MS, the fragrance compounds can be identified individually, based on authentic standards. The steps used for collecting fragrance and control data are presented, from material setup to collecting the data output.

Here, we present a protocol for collecting the floral fragrance volatiles from blooming flowers, using a non-destructive sampling procedure.

אוסף מהיר של ניחוח פרחוני וולאטילס באמצעות מרחב ראש שיטה איסוף נדיפות עבור GC-MS מדגם תרמי

Fragrances of many flower families have been sampled and the volatiles analyzed. Knowing the compounds that make up the fragrances can be an important ...

Biochemistry

A Practical and Low-Cost Setup to Measure Methane in Aqueous Samples

Measuring Dissolved Methane in Aquatic Ecosystems Using An Optical Spectroscopy Gas Analyzer

Measuring greenhouse gas (GHG) fluxes and pools in ecosystems are becoming increasingly common in ecological studies due to their relevance to climate change. With it, the need for analytical platforms adaptable to measuring different pools and fluxes within research groups also grows. This study aims to develop a procedure to use portable optical spectroscopy-based gas analyzers, originally designed and marketed for gas flux measurements, to measure GHG concentrations in aqueous samples. The protocol involves the traditional headspace equilibration technique followed by the injection of a headspace gas subsample into a chamber connected through a closed loop to the inlet and outlet ports of the gas analyzer. The chamber is fabricated from a generic mason jar and simple laboratory supplies, and it is an ideal solution for samples that may require pre-injection dilution. Methane concentrations measured with the chamber are tightly correlated (r2 &#62; 0.98) with concentrations determined separately through gas chromatography-flame ionization detection (GC-FID) on subsamples from the same vials. The procedure is particularly relevant for field studies in remote areas where chromatography equipment and supplies are not readily available, offering a practical, cheaper, and more efficient solution for measuring methane and other dissolved greenhouse gas concentrations in aquatic systems.

This study demonstrates an approach to measure methane gas concentrations in aqueous samples using portable optical analyzers coupled to an injection chamber in a closed loop. The results are similar to conventional gas chromatography, presenting a practical and low-cost alternative particularly suitable for remote field studies.

Measuring greenhouse gas (GHG) fluxes and pools in ecosystems are becoming increasingly common in ecological studies due to their relevance to climate ...

Sampling and Analysis of Animal Scent Signals

We have developed an effective methodology for sampling and analysis of odor signals, by using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry, to understand how they may be used in animal communication. This technique allows the semi-quantitative analysis of the volatile components of odor secretions by enabling the separation and tentative identification of the components in the sample, followed by the analysis of peak area ratios to look for trends that could signify compounds that may be involved in signaling. The key strengths of this current approach are the range of sample types that can be analyzed; the lack of need for any complex sample preparation or extractions; the ability to separate and analyze the components of a mixture; the identification of the components detected; and the capability to provide semi-quantitative and potentially quantitative information on the components detected. The main limitation to the methodology relates to the samples themselves. Since the components of specific interest are volatile, and these could easily be lost, or their concentrations altered, it is important that the samples are stored and transported appropriately after their collection. This also means that sample storage and transport conditions are relatively costly. This method can be applied to a variety of samples (including urine, feces, hair and scent-gland odor secretions). These odors consist of complex mixtures, occurring in a range of matrices, and thus necessitate the use of techniques to separate the individual components and extract the compounds of biological interest.

We have developed an effective methodology for sampling and analysis of odor signals in order to understand how they may be used in animal communication. Particularly, we use headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry to analyze the volatile components of animal odors and scent-markings.

דגימה וניתוח של אותות ריח בעלי חיים

We have developed an effective methodology for sampling and analysis of odor signals, by using headspace solid-phase microextraction coupled with gas ...

Behavior

Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in complex mixtures. It is often used to analyze gasoline, jet fuel, diesel, bio-diesel and the organic fraction of bio-crude/bio-oil. In most of those analyses, the first dimension of separation is non-polar, followed by a polar separation. The aqueous fractions of bio-crude and other aqueous samples from biofuels production have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fractions obtained from the hydrothermal liquefaction of algae were characterized by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation in the second. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column configuration. Results from qualitative characterization of the aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry are highlighted.

A two-dimensional gas chromatography-time-of-flight mass spectrometry method is described for characterization of the aqueous fraction of bio-crude produced from hydrothermal liquefaction of algae. This protocol can also be employed to analyze the aqueous fraction of liquid products from fast pyrolysis, catalytic fast pyrolysis, catalytic deoxygenation and hydro-treating.

אפיון איכותי של השבר מימית מ הידרותרמיות עיבוי של אצות באמצעות גז כרומטוגרפיה 2D עם זמן של הטיסה ספקטרומטריית מסה

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in ...

Nitrogen Compound Characterization in Fuels by Multidimensional Gas Chromatography

Certain nitrogen-containing compounds can contribute to fuel instability during storage. Hence, detection and characterization of these compounds is crucial. There are significant challenges to overcome when measuring trace compounds in a complex matrix such as fuels. Background interferences and matrix effects can create limitations to routine analytical instrumentation, such as GC-MS. In order to facilitate specific and quantitative measurements of trace nitrogen compounds in fuels, a nitrogen-specific detector is ideal. In this method, a nitrogen chemiluminescence detector (NCD) is used to detect nitrogen compounds in fuels. NCD utilizes a nitrogen-specific reaction that does not involve the hydrocarbon background. Two-dimensional (GCxGC) gas chromatography is a powerful characterization technique as it provides superior separation capabilities to one-dimensional gas chromatography methods. When GCxGC is paired with a NCD, the problematic nitrogen compounds found in fuels can be extensively characterized without background interference. The method presented in this manuscript details the process for measuring different nitrogen-containing compound classes in fuels with little sample preparation. Overall, this GCxGC-NCD method has been shown to be a valuable tool to enhance the understanding of the chemical composition of nitrogen-containing compounds in fuels and their impact on fuel stability. The % RSD for this method is &#60;5% for intraday and &#60;10% for interday analyses; the LOD is 1.7 ppm and the LOQ is 5.5 ppm.

Here, we present a method utilizing two-dimensional gas chromatography and nitrogen chemiluminescence detection (GCxGC-NCD) to extensively characterize the different classes of nitrogen-containing compounds in diesel and jet fuels.

אפיון של מתחם חנקן בדלקים על ידי כרומטוגרפיה גז רב מימדית

Certain nitrogen-containing compounds can contribute to fuel instability during storage. Hence, detection and characterization of these compounds is ...

זיהוי טרימתילאמין ברפואה מן החי על ידי Headspace GC-MS

An Improved Technique for Trimethylamine Detection in Animal-Derived Medicine by Headspace Gas Chromatography-Tandem Quadrupole Mass Spectrometry

Animal-derived medicines have distinctive characteristics and significant curative effects, but most of them have an obvious fishy odor, resulting in the poor compliance of clinical patients. Trimethylamine (TMA) is one of the key fishy odor components in animal-derived medicine. It is difficult to identify TMA accurately using the existing detection method due to the increased pressure in the headspace vial caused by the rapid acid-base reaction after the addition of lye, which causes TMA to escape from the headspace vial, stalling the research progress of the fishy odor of animal-derived medicine. In this study, we proposed a controlled detection method that introduced a paraffin layer as an isolation layer between acid and lye. The rate of TMA production could be effectively controlled by slowly liquefying the paraffin layer through thermostatic furnace heating. This method showed satisfactory linearity, precision experiments, and recoveries with good reproducibility and high sensitivity. It provided technical support for the deodorization of animal-derived medicine.

מחבר Spotlight: טכניקה משופרת לזיהוי טרימתילאמין ברפואה שמקורה בבעלי חיים על ידי Headspace גז כרומטוגרפיה-טנדם Quadrupole Mass Spectrometry  

Here, a headspace gas chromatography-tandem quadrupole mass spectrometry (HS-GC-MS/MS) method suitable for the determination of trimethylamine (TMA) in animal-derived medicines is described. The protocol includes sample pretreatment, headspace treatment, analysis conditions, methodological validation, and the determination of TMA in animal-derived medicines.

טכניקה משופרת לזיהוי טרימתילאמין ברפואה מן החי על ידי Headspace Gas Chromatography-Tandem Quadrupole Mass Spectrometry

Animal-derived medicines have distinctive characteristics and significant curative effects, but most of them have an obvious fishy odor, resulting in the ...

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