11.5 : 色谱分辨率

In linear chromatography, as each solute moves along the column, it spreads into a Gaussian distribution, which can lead to overlap on the column.

Chromatographic column resolution is expressed as the ratio of the difference in retention time or volume between two adjacent peaks to their average peak width at the base. An increase in resolution increases the separation of the two peaks.

At a low resolution, the overlap in elution time and volume of two equal-width adjacent peaks is high, meaning significant co-elution of the two solutes. With increasing resolution, the area of overlap decreases.

Because Gaussian curves have a predictable shape, if the peak width at the base is difficult to measure, the equation can be adapted for the width at half the maximum peak height.

In addition, resolution can be calculated via the separation factor—a thermodynamic measure of the relative retention of two solutes expressed as the ratio of the retention factors.

The resolution and column efficiency are linked to these terms by the Purnell equation, or master resolution equation.