GAS-CHROMATOGRAPHIC DETERMINATION OF PHOSPHORUS-CONTAINING PESTICIDE METABOLITES VIA BENZYLATION

Mono- and di-protic alkyl and aryl phosphates, phosphonates, and thio analogs were determined in spiked samples of bacterial growth medium and human urine using a new procedure with a detection limit of less than 2 pmol each. The acids were fully protonated by passing the aqueous samples through BioRad AG 50W-X8 (H+) resin and dried thoroughly before refluxing with 3-benzyl-1-p-tolyltriazene in acetone. The benzyl esters that formed partitioned quantitatively into cyclohexane and were determined by GLC with a flame-photometric detector P mode) and a glass column (5% OV-210 on 80/100 mesh Gas Chrom Q). Linear recovery curves were obtained. Inorganic orthophosphate did not interfere with urine analysis, although it could be easily by Ca(OH)2 precipitation.