Chromatographic Methods: Terminology

Chromatography separates and identifies components by distributing them between a stationary phase, which is usually packed in or attached to a supporting material, and a mobile phase that moves along or through the stationary phase.

When more than one component is present, bands are produced, which can be quantified in a chromatogram using a detector.

The detector response to parameters like solute concentration plotted against the elution time or volume produces a series of peaks called a chromatogram.

The time elapsed from the injection of the mixture to the detector's peak response to an analyte is the analyte's retention time, and the volume of the mobile phase required to elute the analyte is its retention volume.

The width at the base of a chromatographic peak, or bandwidth, is measured at the baseline between the tangents to the inflection points on the sides of the peak.

Another important concept is the peak resolution, measuring the separation of two adjacent peaks with respect to their peak widths at the base.

Additionally, the retention factor, or capacity factor, measures the analyte distribution between the stationary and mobile phases.