Analysis of hair segments for drugs by electrospray high performance liquid chromatography/mass spectrometry

Recently, many studies have reported identification of drugs of abuse in human hair. Researchers have analyzed segments of hair to identify the location of drugs in hair. This data can be used to correlate the time of exposure to the drug, since on the average hair grows 1-1.3 cm/month and drugs incorporate into hair by a simple passive mechanism from blood. To investigate this hypothesis, 10 hair samples from drug abusers were collected upon autopsy and were segmented and analyzed for drugs of abuse by electrospray high performance liquid chromatography/mass spectrometry. Prior to the study, optimum conditions for the analysis were determined. The hair segments were extracted with methanol. Morphine, codeine, 6-monoacetylmorphine, benzoylecgonine and cocaine were determined in the extract from the hair segments. Segmental hair analysis showed generally that the amount of drug increased toward distal ends of hair. This may indicate that drugs incorporate into hair by routes other than simple passive mechanism from the blood stream. Therefore, results from segmental hair analysis which are to be used to determine the history of drug use of an individual must be interpreted with caution.