DETERMINATION OF THE METABOLITES OF THE HERBICIDE DIMETHYL TETRACHLOROTEREPHTHALATE IN DRINKING-WATER BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH GAS-CHROMATOGRAPHY MASS-SPECTROMETRY CONFIRMATION

Two metabolites of the herbicide dimethyl tetrachloroterephthalate, (D CPA), monomethyl tetrachloroterephthalate (MM) and tetrachloroterephth alic acid (TCPA), are assayed via high-performance liquid chromatograp hy with ion pairing. Samples are analyzed via direct injection, withou t preparation, and analyte detection is accomplished with an ultraviol et photodiode array detector, The metabolites are extracted from posit ive samples with a petroleum ether/diethyl ether mixture, derivatized with N,O-bis(trimethylsilyl) trifluoroacetamide, and confirmed byway o f gas chromatography/mass spectrometry, The HPLC analysis of 20 spiked drinking water samples yielded a recovery range of 92-106% with a mea n recovery of 101% for TCPA and a recovery range of 92-101% with a mea n recovery of 96% for MM, The minimum detection limits for TCPA and MM were 2.4 and 2.7 mu g/L, respectively, In addition, the GC/MS analysi s of spiked reagent water yielded mean recoveries of 91% for MM and 86 % for TCPA. Twenty drinking water samples were split and analyzed by t he HPLC and GC/MS methods and by USEPA Method 515.1, Comparable result s were obtained, The HPLC method, which is amenable to automation, typ ically allows for the analysis of up to 40 samples overnight.