Determination of methamphetamine in urine by acyl derivatization and gas chromatography with nitrogen-phosphorus detection

The determination methods for methamphetamine (MA) in urine by gas chromatography with nitrogen phosphorous detection combined with dichloroacetyl, pentafluorobenzoyl, and 3, 5-dinitrobenzoyl derivatization were developed. The procedure was simple and rapid. One millilitre of urine sample was alkalized and extracted with 0. 2 mL of cyclohexane. The acyl derivatization was completed by addition of 10 mu L of acid chloride or anhydride into the extract and placing at room temperature for 5 min. Theresiduary reagent was destroid by washing with alkaline aqueous solution. The orgainc phase was analysed. The sensitivities of these methods were campared each other and with those of acetyl, trifluoroacetyl, pentafluoropropanoyl, heptafluorobutyryl derivatization and non-derivatization methods,which have been reported in literature. The pentafluorobenzoyl and 3, 5-dinitrobenzoyl derivatization methods are more sensitive. The detection limites of the two methods are 3. 0 mu g/L and 4. 6 mu g/L respectively. The determination result of uring samples of subjects digested MA showed that these methods were suitable for analaysis of AM in uring.