Hair analysis forensic applications

The evidence from this laboratory and from others reviewed in this chapter reinforces and extends the serious concern that external contamination of hair by drugs of abuse can easily occur. Any interpretation of hair analysis data should consider the prospect that the sample could have been externally contaminated. The pharmacokinetics of the incorporation of drugs into many tissues has been well elaborated. However, substantial additional information on the mechanisms for incorporation of drugs into hair, the decontamination of hair, the differentiation between exposure to exogenous and endogenous drugs, and the meaning of the presence of metabolites in the hair are needed before hair analysis can be employed in many forensic applications. 

With growing attention to hair analysis for drugs of abuse and pharmaceutical drugs, a number of pharmacological, analytical, and technical problems became of interest, which have been focused in a Consensus Report and revised at the SOFT Conference 1992 in Cromwell, Hartford, CT. Main problems arose with the questions of external contamination, the routes of incorporation of drugs into hair, possible dose-response relationships, interpretation of results, and their application to forensic, clinical, and occupational cases. 

Baumgartner, W. A., Cheng, C. C., Donahue, T. D., Hayes, G. E, Hill, V. A., and Scholtz, H., Forensic drug testing by mass spectrometric analysis of hair. Forensic Applications of Mass Spectrometry, CRC Press, Boca Raton, FL, 1995, 61. 

Until now, most studies have focused on forensic considerations. However, another exciting application of hair anlysis may be clinical investigations. The determination of plasma or urine concentrations of the monitored drugs is commonly used for that purpose however, such analyses may reflect only the exposure within a few days prior to obtaining the specimen. Hair analysis may represent an appropriate alternative, by providing information on the degree of exposure over a long time scale — weeks or months. 

Technically, testing of hair for drugs is no more difficult or challenging than testing in many other "alternative" matrices (for example, liver, bone, etc.). In fact, the application of analytical methods and instrumental approaches are in most cases quite similar, regardless of the initial matrix. At present, hair analysis is routinely used as a tool for detection of drug use in forensic science, traffic medicine, occupational medicine, and clinical toxicology. 

Tagliaro F, Smyth WF, Turrina S, Deyl Z, Marigo M (1995) Capillary electrophoresis A new tool in forensic toxicology. Applications and prospects in hair analysis for illicit drugs. Forensic Sci Int 7(fc93-104. 

Tlien, three decades later, independently but almost simultaneously, Kehoe in Cincinnati [3] and Teisinger in Prague [4] demonstrated the presence of lead in the blood of persons who were not industrially exposed. Over the following years the wide spectrum of application for the analysis of toxic heavy metals in blood endowed this approach with greater importance than hair analysis. However, the sensational results of forensic analysis ensured that hair analysis was not completely forgotten. 

At this initial session, a simple application should be demonstrated. One of the most successful is to explain the presence of trace elements in hair and to then obtain a hair sample (perhaps two) one of which is cleaned with alcohol and the other not. The resultant spectrum obtained on a Ge detector following sample irradiation is used to demonstrate the capabilities of INAA to identify and quantify trace elements in the hair sample. The presenter must explain this forensic application and extend the discussion to further possibilities in trace element analysis in other areas. 

Hair is a special case, and is an attractive target for chemical analysis It is noninvasive to collect, requires relatively simple sample preparation protocols, and provides a historical record of exposure to various chemicals and drugs. Hair is usually collected Ifom the area at the back of the head, and to provide a representative sample, at least 200 mg should be collected. Hair analysis is being often used, especially in forensic applications. 

Moller, M.R., Fey, P., and Wennig, R. (1993) Simultaneous determination of drugs of abuse (opiates, cocaine and amphetamine) in human hair by GC-MS and its application to the methadon treatment program, in Special Issue Hair Analysis as a Diagnostic Tool for Drugs of Abuse Investigation, Forensic Science International, vol. 63 (ed P. Saukko), Elsevier, Amsterdam, pp. 185-206. 

As with urine, saliva (spumm) is easy to collect. The levels of protein and lipids in saliva or spumm are low (compared to blood samples). These matrices are viscous, which is why extraction efficiency of xenobioties amoimts to only 5 to 9%. By acidifying the samples, extraction efficiencies are improved as the samples are clarified, and proteinaceous material and cellular debris are precipitated and removed. Some xenobioties and their metabohtes are expressed in hair. Hair is an ideal matrix for extraction of analytes to nonpolar phases, especially when the parent xenobioties are extensively metabolized and often nondetectable in other tissues (parent molecules of xenobioties are usually less polar than metabolites). Hair is a popular target for forensic purposes and to monitor drug compliance and abuse. Human milk may be an indicator of exposure of a newborn to compounds to which the mother has been previously exposed. The main components of human milk are water (88%), proteins (3%), lipids (3%), and carbohydrates in the form of lactose (6%). At present, increasing attention is devoted to the determination of xenobioties in breath. This matrix, however, contains only volatile substances, whose analysis is not related to PLC applications. 

One of the most famous applications in forensic science is the analysis of Napoleon s hair by ICP-MS after mineralization in concentrated nitric acid whereby an arsenic concentration about 40 times higher than normal (about 40p,gg 1) was measured (see Section 9.5). Ingested arsenic is known to be stored in sulfydryl rich tissue, like hair, nails or skin. ETV-ICP-MS combined with isotope dilution has been employed to measure thallium in human scalp hair from a person poisoned by thallium compared to control subjects, whereby several longitudinal concentration gradients for the analyzed segments (length 10 mm) were obtained.28... 

Hedman, J. and Jangblad, A. (2003). Low copy number (LCN) DNA analysis—A general validation of the specialized DNA analysis method with specific application to telogen hair. Forensic Sci. Int. 136, 35-35. 

Forensic chemistry is concerned with the application of the principles of chemistry and related sciences to the examination of physical evidence collected at scenes of crimes, e.g. blood stains, paint fragments, bomb residue, clothes, drug samples and hair. The samples could provide conclusive evidence linking a suspect to a crime. Results from chemical analysis are usually conclusive and can be used to support eye witness testimony especially when trials take place many months or even years after the offence. 

Meier-Augenstein and Fraser [81] present a case where stable isotope data from human tissue were utilized as forensic intelligence to assist in the identification of a murder victim and subsequently the apprehension of the killers. Rauch et al. [82] demonstrate the application of IRMS to the measurement of stable isotope values (H, C, N) in combination with the measurement of heavy elements (Pb, Sr) of hair and teeth samples from an unknown body in Germany. These analyses assigned the man to Romania, in a situation where traditional forensic techniques (e.g., dental, fingerprint or DNA analysis) could not assist. 

Cheze, M, M. Deveaux, C, Martin, M. Lhermitte, and G. Pepin, 2007. Simultaneous analysis of six amphetamines and analogues in hair, blood and urine by LC-ESl-MS/MS. Application to the determination of MDMA after low ecstasy intake. Forensic Sci Int. 170 100-104. 

When I wrote the first edition of this book in 1994 the use of infrared miCTOscopy in forensic science was new. Since then the proliferation of CSI -type TV shows has plaeed forensic science, and to a point infrared microscopy, squarely in the public eye. This is appropriate since there are many real-world applications of infrared microscopy in forensic science. One application is the analysis of hair and clothing fibers collected at crime scenes, which may lead to someone s arrest. The spectrum of one of the author s hairs (NOT from a crime seene) measured with a micro-ATR accessory is shown in Figure 6.10. 

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