The in vitro differential binding of benzoylecgonine to pigmented human hair samples

Only fragmentary information on the relationship between hair pigmentation (melanin) and the cocaine/benzoylecgonine content of hair samples is available. The in vitro incorporation of benzoylecgonine into the shafts of black, brown, and blond samples of human hair was accomplished. Post digestion analysis and wash samples demonstrate the relative incorporated ions of benzoylecgonine to be black > brown > blond. Melanin content seems to be important. Lightly pigmented blond hairs may be less appropriate samples for benzoylecgonine and cocaine analysis.