Tandem mass spectrometry: a helpful tool in hair analysis for the forensic expert

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Abstract

The Bavarian State Bureau of Investigation in Munich has the exclusive responsibility for investigation of criminal acts. One considerable expertise is that of hair analysis. According to the legal system in Germany, there is a special interest when some clients’ hair tested positive for illicit drugs. An accused with a lot of drugs in his hair will be treated as a supposed addict and will be guaranteed extenuating circumstances. The instrumentation used for hair analysis is a powerful analytical tool: a Varian 3400 gas chromatograph linked to a Finnigan Tandem-MS (TSQ 700). The methanol extraction method is used for the detection of illegal drugs and metabolites: amphetamine, methamphetamine, MDA, MDMA (ecstasy), MDE, MBDB, methadone, THC, EDDP (metabolite of methadone), cocaine, benzoylecgonine, cocaethylene, opiates (dihydrocodeine, codeine, heroin, 6-monoacetylmorphine, morphine, acetylcodeine). For the detection of 9-carboxy-THC by negative chemical ionization the hair sample is hydrolyzed under alkaline conditions. Solid-phase extraction is used for clean-up. The LOQ for the determination of 11-nor-Δ-9-tetrahydrocannabinol-9-carboxylic-acid is 0.16 pg/mg hair. An unsurpassed combination for rendering an expert opinion based on hair analysis may be: a forensic expert using diligence and experience, coupled with the performance of a sophisticated analytical instrument.

Introduction

The 1998 International Workshop in Munich ‘Cannabinoids in Hair’ organized by the ‘Society of Hair Testing’ was presented in the laboratories of two local institutes. One of these institutes is the central police agency for Bavaria (Bavarian State Bureau of Investigation). This State Bureau is exclusively responsible for investigating criminal acts, but it is not responsible for investigation of civil law or administration law cases. No service laboratory for workplace testing has been established.

An essential field of a chemistry and toxicology department is hair analysis. Orders for hair testing will be sent from the court, from the prosecutor’s office and the police. The forensic expert’s skills based on hair analysis will be utilized as corroborative evidence. These skills are mainly used to scrutinize for chronic abuse of illegal drugs or as an adjunct to a medical and physiological examination in order to evaluate criminal responsibility.

In the description of these duties, it is important to emphasize that some clients have a special interest that their hair tests positive for illegal drugs. For example, with regard to the legal system in Germany, a person taken into custody for drug trafficking with no residues of drugs in his hair will probably be sentenced as a dealer. However, an accused with a lot of drugs in his hair could be treated as a supposed addict and will be guaranteed extenuating circumstances. For this reason, some clients are disappointed if the residues of drugs in the hair sample are minimal and not enormous.

Generally, particular information from the mandator about the individual subject can be important for a rendering of an expert opinion. Aspects that could be considered are, for example: when was the person taken into custody? What are the special allegations? Is there a self reported use?

Section snippets

Chemicals and reagents

Methanol, acetonitrile, ethyl acetate, n-hexane, acetone, acetic acid and phosphoric acid were analytical grade (Merck, Darmstadt, Germany). The derivatizing agents penta-fluoropropionic anhydride and hexafluoroisopropanol were purchased from Aldrich (Steinheim, Germany). Reference standard solutions of D5-amphetamine, D5-methylenedioxymethamphetamine, D3-benzoylecgonine, D3-tetrahydrocannabinol, D3-methadone, D3-cocaine, D3-morphine, D3-dihydrocodeine, D3-codeine, D3-6-monoacetyl-morphine,

Results and discussion

The head is an anatomical area where hair samples are collected in the great majority of cases. However, approximately 10% of samples provided for hair analyses in the laboratories of the State Bureau were obtained from beard, pubic, axillary and chest region [1].

A convenient method to isolate drugs and metabolites that are incorporated in hair is methanol extraction [2]. The methanol extraction procedure is suitable for the determination of amphetamine, methamphetamine, MDA, MDMA (ecstasy),

Conclusion

Each forensic expert will appreciate the solid basis of reliable data. He will probably prefer two, three or even more data in order to evaluate the drug history of a certain person. A helpful tool for reaching this goal can be a gas chromatograph/tandem-mass spectrometer in order to detect components and metabolites in very low concentration.

Possible criteria for obtaining a positive hair result as used in the State Bureau are the following.

  • Cocaine positive: only if cocaine exceeds 0.5 ng/mg

Acknowledgements

The author would like to thank, for their excellent support and engagement, Mrs. S. David and Mrs. G. Sichelstiel for sample preparation and Mr. X. Neumeier for performing GC/MS/MS analyses.

References (7)

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