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J Anal Toxicol. 1999 Nov-Dec;23(7):581-5.

Sulfonium salts as derivatizing agents. 3. Quantitation of the cocaine metabolite benzoylecgonine in urine using gas chromatography with ion-pair extraction/on-column alkylation.

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Drug Dependence Research Center, Department of Psychiatry, University of California, San Francisco 94143, USA.


Recent studies have demonstrated the utility of quantitative assays for benzoylecgonine in assessing the efficacy of cocaine-dependence-treatment programs to determine if the amount of cocaine consumed has been reduced. We describe a simple gas chromatographic method for determining benzoylecgonine concentrations in urine. BZE is extracted from urine as an ion pair with tri-n-propylsulfonium ion. Injection into the heated injection port of the gas chromatograph results in thermal conversion of the ion pair to the n-propyl ester of BZE. Using the structural analogue of BZE, m-toluylecgonine, as the internal standard, the analysis is carried out on a (5% phenyl)methylpolysiloxane capillary column with nitrogen-phosphorus detection. There was a good correlation between BZE concentrations determined by gas chromatography-mass spectrometry and concentrations determined by the method described in this paper. Application to cocaine-dependence-treatment programs is discussed.

[Indexed for MEDLINE]

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