Automated trace enrichment for screening and/or determination of primary, secondary and tertiary amphetamines in biological samples by liquid chromatography

A rapid and simple liquid chromatographic method for the automated determin ation of amphetamines in biological fluids was developed. The proposed proc edure is based on the injection of 250 mu L of sample into a 20 x 2.1 mm id precolumn (packed with a 30 mu m Hypersil C-18 Stationary phase) for enric hment and purification of the analytes. Next, the analytes are transferred to a 5 mu m LiChrospher 100 RP18, 125 x 4 mm id analytical column for their separation under reversed-phase conditions. Water was used to eliminate th e matrix components from the precolumn and a 0.2 M phosphate buffer (pH 3) containing 2% triethylamine was the mobile phase for the resolution of the amphetamines. The UV detector was set at 210 nm. The method was applied to the determination of different primary, secondary and tertiary amphetamines in plasma and urine: beta-phenylethylamine, norephedrine, ephedrine, N-met hylpseudoephedrine, pseudoephedrine, N-methylephedrine, amphetamine, 3-phen ylpropylamine and methamphetamine. The method provides satisfactory lineari ty and reproducibility within the tested concentration range (1.0-10.0 mu g mL(-1)) and limits of detection of 50-500 ng/mL(-1).