Abstract
Metsulfuron methyl, its hydroxy metabolite (A1), and its glucose conjugate metabolite (A) were determined in several crops by liquid chromatography (LC) using a simple extraction and cleanup scheme. After the parent and 2 major metabolites were extracted from crops with methanol, metabolite A was enzymatically hydrolyzed to metabolite A1 with β-glucosidase. The treated extracts were cleaned up chromatographically, and then metsulfuron methyl and metabolite A1 were quantitatively determined by reversed-phase LC with UV detection at 254 nm. Recovery of metsulfuron methyl and its 2 metabolites was 90 ± 6% over a range of 0.005 to 0.4 ppm from fortified samples of brown grain, wheat, barley, sugarcane stalk, and oat straw. Method detection limits (MDLs) were 0.005 ppm for metsulfuron methyl, 0.006 ppm for metabolite A, and 0.003 ppm for metabolite A1 in such crops as brown grain, wheat, barley, and sugarcane, and 0.01 ppm for metsulfuron methyl, 0.015 ppm for metabolite A, and 0.01 ppm for metabolite A1 in oat straw. The MDLs were estimated on the basis of a signal-to-noise ratio of 5 within a confidence interval of 95%. The method has potential application for the analyses of these analytes in other crops and feeds and may be applicable to other sulfonylurea herbicides.
Quantitation of Multiple Sphingolipid Classes Using Normal and Reversed-Phase LC–ESI–MS/MS: Comparative Profiling of Two Cell Lines
