SOFT/TIAFT 98 - Quantitation of Cocaine, Benzoylecgonine, Cocaethylene, Methylecgonine and ...

SOFT - TIAFT 1998

Poster Session 1

Wednesday October 7, 1998

QUANTITATION OF COCAINE, BENZOYLECGONINE, COCAETHYLENE, METHYLECGONINE AND NORCOCAINE IN HUMAN HAIR BY POSITIVE ION CHEMICAL IONIZATION (PICI) GAS CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY (GC/MS/MS)

James A. Bourland, Eugene F. Hayes, Stacy A. Sweeney and Raymond C. Kelly

Associated Pathologists Laboratories, 4230 S. Burnham Avenue, Suite 250, Las Vegas, Nevada 89119, USA

A total of 30 human head hair samples were analyzed for cocaine (COC), cocaethylene (CE), benzoylecgonine (BE), methylecgonine (EME), and norcocaine (NCOC) utilizing a sensitive positive ion chemical ionization (PICI) gas chromatography tandem mass spectrometry (GC/MS/MS) method. All 30 hair samples had been previously submitted to the laboratory and had confirmed positive for cocaine. Hair samples (20 mg each) were cut into small segments (2-5 mm) and incubated overnight at 45^oC in 0.1 N HCL after the addition of 50 µL of an internal standard mix of COC-d₃ (1 ng/mg), BE-d₃ (0.5 ng/mg), EME-d₃(0.25 ng/mg) and NCOC-d₃ (0.25 ng/mg). The samples were then extracted with a solid phase extraction procedure using World Wide Monitoring columns. The final extract was evaporated to dryness and derivatized with 50 mL of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and 50 mL of trifluoroacetic anhydride (TFAA) at 90^oC for 15 min. The derivatized samples were allowed to cool to room temperature, evaporated to dryness and then reconstituted in 50 mL of ethyl acetate.

Parent set masses (bold ions) and product ions were m/z 304 and m/z 182 and 82 (COC), m/z 307 and m/z 185 and 85 (COC-d₃), m/z 318 and m/z 196 and 82 (CE), m/z 440 and m/z 318 and 105 (BE), m/z 443 and m/z 321 and 105 (BE-d₃), m/z 296 and m/z 182 and 82 (EME), m/z 299 and m/z 185 and 85 (EME-d₃), m/z 403 and m/z 386 and 105 (NCOC), m/z 406 and m/z 389 and 105 (NCOC-d₃).

Quantitation was accomplished by calculating the area ratio of the higher mass product ion (underlined ions) of analyte to the respective internal standard based on multilevel calibrations from 0.01 to 10 ng/mg. The GC/MS/MS method had an LOD of 0.01 ng/mg for all five analytes and an LOQ of 0.05 ng/mg.

COC, BE and EME were detected in all 30 samples and CE and NCOC were found in 19 and 28 samples, respectively. The average relative percentages of each metabolite normalized to the cocaine concentrations were 19.5%, 13.3%, 1.9%, and 3.4% for BE, CE, EME and NCOC, respectively.

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