High performance liquid chromatography with chemiluminescence detection of methamphetamine and its related compounds using 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole.

Abstract

A high performance liquid chromatographic assay of methamphetamine (MP) and its related compounds, i.e. ephedrine (EP), norephedrine (NE), p-hydroxymethamphetamine (p-HMP), p-hydroxyamphetamine (p-HAP) and amphetamine (AP), with peroxyoxalate chemiluminescence detection has been developed. 4-(N,N-Dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) was used as a fluorescent labeling reagent. A mixture of hydrogen peroxide and bis[4-nitro-2-(3,6,9-trioxadecyloxycarbonyl)phenyl] oxalate in acetonitrile was used as a postcolumn chemiluminogenic reagent. DBD derivatives of MP and its related compounds were separated by a gradient elution with acetonitrile and 0.01 M imidazole buffer (pH 7.0) within 65 min. The detection limits (S/N = 3) for the proposed method for MP, AP, EP, NE, p-HMP and p-HAP were 27, 100, 40, 133, 25 and 133 fmol on column, respectively. The recoveries of these compounds with normal urine samples were 87.4-106.4%. The method was successfully applied to the assay of MP and its metabolites in urine samples from MP addicts. A good linear correlation for the resulted amounts of MP or AP between the proposed method and gas chromatography was obtained (r = 0.993 for MP or 0.991 for AP).