Hair analysis extraction methods

Due to the low amount of specimen used for hair analysis and the low concentration of drugs and their metabolites in hair, extraction procedures are mostly necessary to concentrate the analytes in the tested solution. Various methods have been used for this step. The variety of described procedures show that there is no universal solution. The choice of an extraction procedure may be influenced by the kind of drug and drug metabolite(s) to be analyzed and the method used for the subsequent analysis. Preceding the real extraction, there are four treatments with more or less intermethodical differences to prepare the hair matrix for the extraction ... 

Preparing the sample is a key step in all biological analyses, and hair analysis is no exception to this rule. Over the last ten years, there has been an ever increasing interest in the use of supercritical fluid extraction (SFE) as an alternative to traditional methods of preparing samples. The driving force behind this development is, without doubt, the need for a simple, rapid, automated, and selective method which should also be environmentally friendly. In this context, the use of supercritical fluids fulfills these conditions, due to their unique physicochemical properties. The following is a list of advantages ... 

Supercritical phase extraction is the chosen method for extracting drugs, including opiates, cocaine, and methadone from a solid matrix such as hair. In its present state, supercritical phase extraction can be used with these three groups of drugs. In the near future, however, it is probable that this method will be applicable to other drugs and even to other medical substances. At that time, SFE will probably become the reference method for hair analysis. 

Morrison, J.F., MacCrehan, W.A., Selavka, C.M., Evaluation of supercritical fluid extraction for the selective recovery of drugs of abuse from hair, 2nd International Meeting on Clinical and Forensic Aspects of Hair Analysis, National Institute on Drug Abuse. Special Publication, submitted, 1995. Welch, M.J., Sniegoski, L.T., Allgood, C.C., Habram M., Hair analysis for drugs of abuse evaluation of analytical methods, environmental issues, and development of reference materials, /. Anal. Toxicol, 17(6), 389-398, 1993. 

Initial studies performed during the late 1970s and early 1980s revealed the presence of benzoylecgonine (cocaine metabolite) and morphine (heroin metabolite) in hair. Since then, fiu-ther studies of hair analysis have identified additional cocaine analytes and opioids. The aim of this chapter is to provide a review of the analytical techniques utilized in hair analysis, including preliminary wash/decontamination procedures, methods of analyte isolation and pmification, and analysis of the hair extracts. In addition, this chapter will present research findings. 

As previously mentioned, besides conventional matrices such as urine and blood, alternative matrices have become of great interest in toxicology. Different reviews describe the analysis of dmgs of abuse in saliva, sweat, and hair [53-56]. For conventional matrices, LLE and SPE are usually the methods of choice. However, for hair analysis, a more drastic extraction step is necessary initially, followed by a purification step [57]. 

Ingested arsenic is known to be not only excreted by urine, but also to be stored in sulfydryl rich tissue like hair, nails or skin. A method of extracting arsenic species from hair and nail samples has been developed for the analysis of the total arsenic concentration, inorganic As ( ) and As... 

Chemical analysis of hair samples may also provide a method for examining chronic mycotoxin exposures. In 2003, Sewram et al. (2003) reported that human hair testing could be used to detect fumonisins. After extraction and clean up, high performance liquid chromatography coupled to electrospray ionization-mass spectrometry (HPLC-ESI-MS) was able to detect fumonisin Bi, fumonisin B2, and fumonisin B3 from human hair samples (Sewram et al., 2003). However, these were... 

Several variables must be considered in the analysis of hair besides the decontamination procedure. The most important is the method by which drugs are to be extracted from the hair matrix. Because no extraction solution can remove all of the drug present, dissolution of the hair matrix before extraction of the drug appears essential to achieve complete removal for analytical purposes. 

The repeatability of the overall method proposed (SFE extraction and GC analysis) is determined by using optimum conditions previously established, on soaked hair. 

In forensic cases, DNA samples can be extracted and purified from small specimens of skin, blood, semen, or hair roots collected at the crime scene. DNA that is suitable for analysis even can be obtained from dried stains of semen and blood. The RFLP analysis performed on these samples then is compared to those performed on samples obtained from the suspect. If the RFLP patterns match, it is then beyond reasonable doubt that the suspect was at the crime scene. In practice, several different probes containing different types of repetitious sequences are used in the hybridizations in order to satisfy certain statistical criteria for absolute, positive identification. The use of different restriction enzymes allow for accuracies in positive identifications of greater than one in 100 million. In recent years, polymerase chain reaction (PCR), a method that amplifies DNA, has made it possible for very small amounts of DNA found at crime scenes to be amplified for DNA fingerprinting analysis. Using specific probes to prime DNA polymerase, many copies of the targeted areas of DNA can be synthesized in vitro and subsequently analyzed. 

Hair-cleaning methods may be classihed according to the following categories chemical and physical properties, microscopic methods, and subjective or sensory evaluation procedures. Chemical or physical methods may involve either direct analysis of the hair itself [13, 20] or analysis of hair extracts [17,18]. For direct analysis of hair, chemical methods such as... 

Finally, studies of alcohols present in hnman saliva nsing selective membrane extraction and a GC-DMS detector and a method for rapid analysis of hair based on ESI-IM-MS were published. " ... 

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