Analysis of phencyclidine and cocaine in human hair

David Allan Kidwell, 1 Ph. D.

Analysis of Phencyclidine and Cocaine in Human Hair by Tandem Mass Spectrometry

REFERENCE: Kidwell, D. A., "Analysis of Phencyclidine and Cocaine in Human Hair by Tandem Mass Spectrometry," Journal of Forensic Sciences, JFSCA, Vol. 38, No. 2, March 1993, pp. 272-284. ABSTRACT: A confirmation procedure for the analysis of cocaine, benzoylecgonine, ecgonine, andphencyclidine (PCP) in human hair using tandem mass spectrometry has been developed. This procedure requires no solvent extraction and thus can examine the metabolites of drugs such as cocaine. Hairs from six cocaine users were examined and the amount of cocaine and its ratio to the metabolites was not correlated to the reported use pattern. Only PCP was detected in the hair from a PCP user, nometabolites were found. In passive exposure experiments, hair was found to tightly absorb PCP from aqueous solutions, which mimics the incorporation of PCP by the body. These results indicate that drugs may be absorbed onto the hair of nonusers and become tightly bound.

KEYWORDS: toxicology, cocaine, tandem mass spectrometry, hair

The analysis of hair for drugs of abuse has several advantagesover the testing of urine. Some drugs, like morphine, have been shown to be stable in hair and not leached for long periods of time [1]. In addition, because drugs are often not entirely removed from hair by normal treatments, hair analysis can be repeated with another sample if the analytical results are questioned. In contrast, most drugs are rapidly cleared from urine within a day or two [2]and therefore consecutive urine specimens would not have the same concentrations of drugs due to metabolism and clearance. Because hair grows at a relatively constant rate of about 1 cm/month, [3] hair analysis also provides a long-term profile of drug use, which may aid as an independent check on an individual's veracity, if urinalysis results are called into question. Hair analysis for cocaine andphencyclidine (PCP) has been performed by extraction and detection of the drug in the extract by radioimmunoassay [1,4-8]. Recent work on cocaine has concentrated on GC/MS confirmation of the drug of abuse in an extract of the hair [6-8]. Extraction is time consuming and requires 30 to 40 pieces of hair the size of a thin pencil (about 250 mg). Moreover, for cocaine, the strong acids necessaryfor extraction may degrade the cocaine. These degradation products are the same as the metabolites. Thus the metabolites cannot be determined directly, which may be useful in distinguishing passive from active exposure.

Received for publication 8 July 1991; revised manuscript received 12 Aug. 1992; accepted for publication 13 Aug. 1992. 1Research Scientist, Naval Research Laboratory, Washington,DC. This work was presented, in part, at the 36th ASMS Conference on Mass Spectrometry and Allied Topics, 5-10 June 1988, San Francisco, CA and the S.O.F.T. Conference on Hair Analysis for Drugs of Abuse, 27-29 May 1990, Washington, DC.
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Copyright © 1993 by ASTM International

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Cocaine and benzoylecgonine ratios have been measured inhair after digestion of the hair with enzymes and extraction of the digest [9,10]. However, the digestion conditions used [9] were derived from those used to extract D N A from hair for forensic purposes [11] and produce a solution from which it is extremely difficult to extract benzoylecgonine. Likewise, none of the other metabolites of cocaine have been measured due to the difficulty of theirextraction. This research had three main objectives: 1) determine which metabolites were present in hair from cocaine and PCP users; 2) explore the use of thermal desorption tandem mass spectrometry to eliminate the problems associated with digestion of hair; 3) demonstrate that analysis can be performed on single hairs using tandem mass spectrometry and that the metabolites as well as the parent...