Rapid and simple method for extraction and determination of imidazolinone herbicides in soil

A rapid, simple and accurate method for the simultaneous determination of residues of the imidazolinone herbicides (imazapyr, imazaquin, imazamethabenz and imazamethabenz-methyl) in soil is described. The basis of the method is the formation of a supernatant by sonication of the soil with 0.1 M KCl. After removal from the soil particles, the pesticides are quantified by reversed-phase liquid chromatography-mass spectrometry with an electrospray interface (LC-ESI-MS). Recoveries from a variety of soil types, fortified over the range of 50–200 ppb, are essentially quantitative for each imidazolinone and the detection limits (signal-to-noise ratio = 3) of the method are always lower than 14 ng/g