Retention time

The time taken for a particular substance that has been broken out of a solution (a solute) to move through the chromatography column; more simply, how long it takes for the substance intended to be detected to move to a point where it is detected.

Retention time with Gas Chromatography Mass Spectrometry and Liquid Chromatography Mass Spectrometry testing is the manner in which the gas or liquid being tested breaks down; important because the use of a reagent for vaporization or liquefaction that has a retention time too close to the substance being tested for, may give a false positive.