Analysis of Pesticides and Related Compounds

Non-Technical Summary: The pesticide laboratory supports persons engaged in the agricultural sector, the South Dakota Department of Agriculture, and the land grant mission of the university through the Agricultural Experiment Station by providing pesticide formulation and residue analysis as a service to the people of the state and region. While the laboratory performs many types of analysis, the bulk of the work is herbicide analysis requested in trying to determine the cause of crop injury. The laboratory deals directly with the public as well as with companies and agencies, explaining the relevance of the data obtained and cautioning what may or may not be possible through the pesticide analyses requested. <P> Approach: The pesticide laboratory uses primarily standard methods or minor variants on those methods for a range of residue analysis. These methods will be continued for routine applications as part of the ongoing mission of the laboratory. They will be expanded, or new methods added, to add capability for analysis of new compounds. The GC/MS and LC/MS/MS methodology commonly used is usually specific enough for good identification even when sample preparation is minimal. However, some compounds chromatograph poorly (e.g., mesotrione or similar ketones), and the planned approach is in altering chromatographic conditions or use of additives to minimize the tailing or poor peak shape. Where new, more sensitive methods are being employed, our practice is to work for recovery with spiked (fortified) blanks first, then to compare results of actual samples analyzed by different methods. The laboratory is in communication with many clients in the agricultural sector, and this is where we learn of new needs and problems. As part of the upgrading of the LIMS (laboratory computer) system, we are presently working with the company to tailor their product to the laboratory's needs.