A New GC-MS Method for the Determination of Five Amphetamines in Human Hair

A new gas chromatography-mass spectrometry method allows simultaneous identification and measurement of five amphetamine-type drugs in hair. Hair samples are hydrolyzed in sodium hydroxide, extracted with a solvent mixture, and derivatized before analysis. The method is accurate to within ±9% and precise, with coefficients of variation below 8%. Detection limits range from 0.007 to 0.045 ng/mg depending on the drug. In 24 positive hair specimens, average concentrations were 0.88 ng/mg for amphetamine, 10.14 ng/mg for methamphetamine, 1.30 ng/mg for MDA, and 8.87 ng/mg for MDMA; only one specimen contained MDEA at 0.84 ng/mg.

Study at a glance

Abstract

A new gas chromatography-mass spectrometry method for the simultaneous identification and quantitation of amphetamine (AP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethamphetamine (MDEA) in hair is proposed. Hair was hydrolyzed in 1 M NaOH at 40 degrees C, subjected to extraction with 4:1 (v/v) methylene chloride/isopropanol, and derivatized with pentafluoropropionic anhydride (PFPA) and ethyl acetate. Calibration curves for the five analytes were constructed over the concentration range 0.5-25.0 ng/mg, using their pentadeuterated analogues as internal standards. The limits of detection and quantitation obtained were 0.045 and 0.151 ng/mg for AP; 0.014 and 0.048 ng/mg for MA; 0.013 and 0.043 ng/mg for MDA; 0.017 and 0.057 ng/mg for MDMA; and 0.007 and 0.023 ng/mg for MDEA. The accuracy of the method was found to be in the range +/- 9%, and the coefficients of variation were less than 8%. Overall, 24 hair specimens tested positive for one or more amphetamines, with average concentrations of 0.88 ng/mg for AP, 10.14 ng/mg for MA, 1.30 ng/mg for MDA, and 8.87 ng/mg for MDMA. Only one specimen tested positive for MDEA with a concentration of 0.84 ng/mg.