AGRO 22 |
| Exposure to azinphos-methyl is typically assessed by determination of dialkylphosphate metabolites in urine. This approach assumes that metabolism of azinphos-methyl is the only source of urinary dialkylphosphate compounds. However, recent work has indicated that dialkylphosphates may be found on fruit treated with azinphos-methyl in the absence of metabolism. Exposure to these pre-existing dialkylphosphates would also lead to elevated urinary levels in exposed individuals. Apples were collected at regular intervals over a four-week period between treatment and harvest. Fate of azinphos-methyl and formation of dialkylphosphates in apples were studied using LC/APCI/MS. This technique offers several advantages over more commonly used GC analysis. Accurate quantitation by GC is problematic as azinphos-methyl is thermally unstable and the metabolites require extensive derivatization prior to GC analysis. These problems do not arise with LC, and the use of APCI/MS permits greater confidence in identification and quantitation of analytes. |
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Agrochemical Residue & Metabolism Chemistry
1:45 PM-4:35 PM, Sunday, August 19, 2007 BCEC -- 259B, Oral
Division of Agrochemicals |