|Marek, L - MN DEPT. AGRICULTURE|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 11, 1996
Publication Date: N/A
Interpretive Summary: Since the early 1980's, there has been a dramatic increase in the number of and use of sulfonylurea herbicides to control broad-leaved weeds in cereal crops. Because of the low application rates of these chemicals, less than 4 oz/acre, analysis at the trace levels (parts per billion, ppb) necessary to monitor environmental fate has been difficult. Existing methods have numerous limitations: some are limited to soil containing only one herbicide; some do not have the required levels of sensitivity; and all methods lack confirmation of the herbicide. For confirmation, sulfonylurea herbicides could be determined by a promising method using high performance liquid chromatography-electrospray-mass spectrometry (HP- LC-EC-MS); separation of herbicides by HPLC followed by quantitation and confirmation by MS would require no special handling or clean-up steps. This paper reports the extraction, separation, quantitation, and confirmation of four sulfonylurea herbicides in soil at ppb levels by LC- ES-MS. This multiresidue method should also be appropriate for other sulfonylurea and polar herbicides. Research Scientists and regulatory agencies now have a multi-residue analytical method for sulfonylurea herbicides so research on and monitoring of these herbicides can be performed at the trace levels needed to determine environmental fate.
Technical Abstract: A multi-residue method for the determination of chlorsulfuron, metsulfuron methyl, thifensulfuron methyl, and triasulfuron in soil by high performance liquid chromatography-electrospray-mass spectrometry (LC-ES- MS) is reported. A clay loam soil, spiked at 6.0 ug kg**-1 with all four herbicides, was extracted with 0.1 M ammonium carbonate and the extract cleaned up by C18-SPE. The herbicides were quantified by SIM. The percent recoveries were: chlorsulfuron, 80.1 plus or minus 7.9 percent; metsulfuron methyl, 99.4 plus or minus 8.5 percent; thifensulfuron methyl, 95.9 plus or minus percent; and triasulfuron 100.5 plus or minus 24.3 percent. We have shown that we can analyze and confirm four 4-methoxy-6- methyl-1,3,5-triazin-2-yl containing sulfonylurea herbicides in soil by LC-ES-MS. This multiresidue method should also be appropriate for other sulfonylurea and polar herbicides.