Determination of chlormequat residues in cotton seed by gas chromatography

Abstract A simple and sensitive method to determine chlormequat (chlorocholine chloride) residues in plant tissue has been devised. The technique is based on an in‐vitro multi‐step reaction where chlormequat is initially N‐demethylated with potassium pentafluorothiophenolate followed by a further reaction with excess reagent to produce a pentafluorothiophenyl derivative. Electron capture detection and mass spectrometry were used for quantitative determination and identification. The method was applied to the analysis of cotton seed harvested from cotton plants treated with various concentrations of chlormequat.