Hair Analysis for Drugs of Abuse: Evaluation of Analytical Methods, Environmental Issues, and Development of Reference Materials*

Abstract

Methods for extraction of cocaine, some of its metabolites, morphine, and codeine from hair and methods for analyzing the extracts have been investigated. Results of these studies have shown that extractions with 0.1N HCl are efficient at removing the target compounds from hair and appear to be as effective as enzymatic digestions that dissolve the hair. GC/MS with either electron ionization or chemical ionization was found to provide accurate and unambiguous determinations of the target compounds. Tandem mass spectrometry (MS/MS) also provided accurate results when performed on extracts from hair, but results were ambiguous when MS/MS was performed on hair segments directly. Environmental issues, including the removal of powdered and vapor-deposited cocaine from the hair surface and the effect of various hair treatments on the levels of cocaine entrapped in hair, have also been investigated. Removal of cocaine deposited on hair was incomplete by all approaches tested, making differentiation of hair of cocaine users from hair with environmental exposure of cocaine difficult. Cocaethylene, a cocaine metabolite believed to be formed in the liver, was found in the hair of some cocaine users and may be a good marker for proving drug use. Common hair treatments, such as shampoos, conditioners, and peroxide bleaches, reduced cocaine levels in a fortified hair material by 60 to 80% after 30 treatments. Finally, to assist laboratories in evaluating the accuracy of their methods, two human hair reference materials with recommended concentrations of cocaine, benzoylecgonine, morphine, and codeine determined by GC/MS have been developed.

Recreational Drug Use: A Major Risk Factor for Gastroschisis?

“…Indeed, even specialised washing solutions advertised for "the removal of medications, chemical build up and other unwanted impurities in the hair shaft" fail to completely remove drugs of abuse from the hair leaving detectable amounts in the hair shaft (Rohrich et al 2000b). Similarly hair preparations such as, hair dye, bleach and perming solutions reduce the amount of the drug in the hair but the drug still remains detectable (Welch et al 1993), (Marsh et al 1995). Evidence of the long term stability of these drugs within the hair once bound into the matrix comes from the detection of cocaine in the hair of pre-Columbian and Egyptian mummies (Cartmell et al 1991), (Balabanova and Wof, 1989) and post-mortem findings of arsenic in the hair of Napoleon Bonaparte and laudanum in the hair of the romantic poet Keats, (Smith et al 1962), (Lyon, 1986 …”

Influence of the cosmetic treatment of hair on drug testing

“…Many factors are likely to affect the concentration of drugs in hair and thus complicate the interpretation of results from these analyses. These factors include, but are not limited to hair colour or melanin content [1,2] physicochemical properties of drugs, such as lipophilicity, melanin affinity and membrane permeability [3] structural factors of drugs [4] external contamination [5] and cosmetic treatment of hair [6][7][8][9][10][11]. Very little has been published about the effects of cosmetic treatment on drug contents in hair.…”

“…Baumgartner et al [6] showed that daily shampooing does not significantly affect the drug content in hair. In studies with various hair treatments, Welch et al [7], found that drug levels can be reduced but probably not eliminated by any reasonable treatment conditions. Blank and Kidwell's studies on external contamination [8] demonstrated that hair treated by dyeing incorporated externally applied drugs.…”

Two new standard reference materials for the determination of drugs of abuse in human hair

“…The methods were independent in several respects, different analyst, different solid-phase extraction, derivatization (GC/MS) versus no derivatization (LC/MS), different chromatographic introduction, different ionization processes, and different ions monitored, although both used the same extraction procedure and isotope-labeled internal standard. The same extraction procedure was used because it produced the highest and most reproducible recoveries among several approaches tested [13]. Both methods used the same deuterated internal standards, which were chosen because they were commercially available, had high isotopic enrichments, and maintained mass differences from the unlabeled compounds for fragment ions measurements.…”