NARROW-BORE HPLC IN COMBINATION WITH FLUORESCENCE AND ELECTROSPRAY MASS-SPECTROMETRIC DETECTION FOR THE ANALYSIS OF COCAINE AND METABOLITESIN HUMAN HAIR

A simple, but sensitive and specific, high-performance liquid chromato graphic assay for cocaine, cocaethylene, and benzoylecgonine is descri bed. Using direct fluorometric detection, the procedure is particularl y interesting for the routine analysis of human hair samples. In the s ample preparation part, the hair samples are cut and washed and two in ternal standards with close structural resemblance to benzoylecgonine and cocaine as well as to cocaethylene are added. Subsequently, the ha ir samples are homogenized, hydrolyzed overnight in a 0.1 M HCl soluti on at 56 degrees C, and extracted on IST Confirm HCX solid-phase extra ction columns. Chromatographic separation is achieved on a narrow-bore Hypersil BDS C-18 column (125 x 2.1 mm, 3 mu m) by gradient elution w ith an ammonium acetate buffer-methanol/acetonitrile mixture. For the fluorometric detection, excitation and emission wavelengths of 242 and 315 nn, respectively, are used, This analysis protocol affords a meth od of high sensitivity and specificity which has been fully evaluated and validated. The data presented show good accuracy and linearity wit h excellent reproducibility and recovery. Because unequivocal identity confirmation is mandatory in forensic applications, an extension of t he analysis protocol was accomplished toward mass spectrometric detect ion. We succeeded in a simple methodological transfer from LC/FL to LC /ESI-MS/MS, thus providing two complementary approaches after a single , common sample-processing step. Hair samples from 29 fatalities, all known drug users and suspected victims from a drug overdose, were anal yzed in this way. Of the investigated samples, 12 were positive and th e concentrations found range from 0.98 to 938 ng/mg of hair for cocain e and from 1.45 to 388 ng/mg of hair for benzoylecgonine. Traces of co caethylene were also found in two of the hair samples. The results obt ained with LC/ESI-MS/MS were in close agreement with those obtained wi th LC/FL, positively confirming the isolates' identity and structure b y means of the resulting MS/MS spectra.