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United States Department of Agriculture

Agricultural Research Service

Title: Lc-Ms Analysis of Polar Pesticides in Soil

Authors
item Marek, Le Etta - MN DEPT OF AGRICULTURE
item Koskinen, William

Submitted to: American Laboratory
Publication Type: Trade Journal
Publication Acceptance Date: April 10, 1997
Publication Date: N/A

Interpretive Summary: Analysis of some newer classes of pesticides, in environmental samples presents greater challenges to the analyst than older chemicals. For instance, they are applied in the environment at much lower rates, less than 4 oz/acre, than the older pesticides and analysis by traditional methods is often not satisfactory. Methods are needed for the analysis of these pesticides and their metabolites at the desired level of sensitivity (parts per billion, ppb) for environmental purposes. A promising method for these pesticides, is high performance liquid chromatograph-electrospray- mass spectrometry (LC-ES-MS). We have developed a multiresidue method of analysis for 8 sulfonylurea herbicides in soil at 6 ppb. Recoveries of chlorsulfuron, metsulfuron methyl, nicosulfuron, sulfometuron methyl, thifensulfuron methyl, and triasulfuron are all 100 percent. Recoveries of primasulfuron methyl (45 percent) and chlorimuron ethyl (69 percent), are still acceptable. This method could easily detect concentrations at less than 0.1 ppb. This multiresidue method also enables the analysis of a new insecticide imidacloprid and its metabolites at the desired levels of sensitivity for environmental fate in soil and water. Research scientists and regulatory agencies now have a multiresidue analytical method for some newer pesticides so research on and monitoring of the chemicals can be performed at the trace levels needed to determine environmental fate.

Technical Abstract: Analysis of some of the newer pesticides, such as sulfonylurea herbicides (SUs) and imidacloprid insecticides, in environmental samples presents greater challenges to the analyst than older chemicals. For instance, they are applied in the environment at much lower rates than the older pesticides. With these pesticides, analysis by traditional methods, such as sby HPLC or GC, is often not satisfactory. Methods are needed for the analysis of these pesticides and their major metabolites at the desired level of sensitivity for environmental purposes, and that can be used for confirmation. A promising multiresidue analytical method for polar pesticides is high performance liquid chromatograph-electrospray-mass spectrometry (LC-ES-MS). We have developed a multiresidue method of analysis for 8 SUs in soil at 6 ug kg-1. The recoveries of chlorsulfuron, metsulfuron methyl, nicosulfuron, sulfometuron methyl, thifensulfuron methyl, and triasulfuron are all 100 percent. The recoveries of primisulfuron methyl (45 percent) and chlorimuron ethyl (69 percent), although lower, are still acceptable. This method could easily detect concentrations at less than 0.1 ug kg-1. We have also shown that the LC-ES- MS method also enables that analysis of imidacloprid and its metabolites at the desired levels of sensitivity for environmental fate in soil and water, at levels comparable to the sulfonylurea herbicides.

Last Modified: 7/24/2014