Identification of cocaine analytes in fingernail and toenail specimens

Fingernail and toenail specimens were obtained from 18 suspected cocaine users. The nails were cut, heated under methanolic reflux, and the methanolic extracts were purified by solid-phase extraction. Gas chromatography/mass spectrometry was utilized for the qualitative and quantitative analysis of nine cocaine analytes. Comparison of conventional postmortem analysis of blood and urine with nail analysis revealed a marked increase in the detection of cocaine use by nail analysis. Cocaine analytes were present in 14 (82.3%) subjects utilizing nail analysis. Out of those 14 subjects, only 5 (27.7%) were positive by conventional postmortem drug analysis. Cocaine and benzoylecgonine were the predominant analytes in all positive nail specimens. Anhydroecgonine methyl ester, ecgonine methyl ester, ecgonine ethyl ester, cocaethylene, norcocaine, and norbenzoylecgonine were detected in a limited number of specimens. The ratio of cocaine to benzoylecgonine ranged from 2-10:1. These findings suggest that nails may be a useful alternative matrix for the detection of cocaine exposure.