MICROWAVE-ASSISTED EXTRACTION COUPLED WITH LIQUID-CHROMATOGRAPHY ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY FOR THE SIMPLIFIED DETERMINATIONOF IMIDAZOLINONE HERBICIDES AND THEIR METABOLITES IN PLANT-TISSUE

The imidazolinones are a significant new class of low-use-rate, reduce d-environmental-risk herbicides for protection of a wide variety of ag ricultural crops. Current residue methodologies for determining the im idazolinones and their metabolites in crops involve laborious, time-co nsuming cleanup procedures after an aqueous/organic extraction. Using imazethapyr, the most widely utilized member of the class, and its met abolites as representatives, liquid chromatography/electrospray ioniza tion mass spectrometry was found to permit processing as little as 1% of the extract normally processed through the existing methods,; Micro wave-assisted extraction aided in the shortened cleanup procedure by p roviding a 100% aqueous initial extract. Over a range of 11 different commodities, average recoveries for imazethapyr, its hydroxy metabolit e, and the glucose conjugate were 100%, 102%, and 97%, respectively. T he simplicity and general applicability of this analytical approach re duced not only sample analysis time but also, perhaps even more import antly, method development time.