ISSN: 0022-1198
CODEN: JFSCA
Page Count: 3

Elimination of Fluconazole Interference in Gas Chromatography/Mass Spectrometric Confirmation of Benzoylecgonine, the Major Metabolite of Cocaine Using Pentafluoropropionyl Derivative
Dasgupta, A
Director of Clinical Chemistry and Toxicology, Associate Professor of Pathology, University of New Mexico Health Sciences Center, NM

Mahle, C
Resident in Pathology, University of New Mexico Health Sciences Center, NM

McLemore, J
Resident in Pathology, University of New Mexico Health Sciences Center, NM

(Received 14 August 1995; accepted 16 October 1995)

Abstract

Cocaine is a widely abused drug and causes death from overdose. Benzoylecgonine, the major metabolite of cocaine in urine is usually confirmed after derivatization by gas chromatography/mass spectrometry to demonstrate cocaine abuse. Recently, Wu et al. demonstrated that fluonazole coelutes with benzotlecgonine after conversion to trimethylsilyl analogs and causes false-negative result in the confirmation test. However, fluconazole did not interfere with the screening assay using a enzyme multiplied immunoassay technique. We demonstrated that by converting benzoylecgonine to the corresponding pentafluoropropionyl derivative, the interference of fluconazole can be completely eliminated. The pentafluoropropionyl derivative of benzoylecgonine eluted at 14.7 min while the derivatized fluconazole eluted at 15.6 min. The mass spectral fragmentation pattern of derivatized benzoylecgonine was distinctively different from the mass spectral features of derivatized fluconazole in both electron ionization and chemical ionization mode of operation of mass spectrometers. The quantitation of benzoylecgonine in positive urine specimens has not affected when the specimens were supplemented with 50 μg/mL of fluconazole.

Keywords:
forensic science, fluconazole, benzoylecgonine, pentafluoropropionyl derivative

Paper ID: JFS13946J
DOI: 10.1520/JFS13946J
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