Fully automated determination of amphetamines and synthetic designer drugs in hair samples using headspace solid-phase microextraction and gas chromatography-mass spectrometry

This study describes a fully automated procedure using alkaline hydrolysis and headspace (HS) solid-phase microextraction (SPME) followed by on-fiber derivatization and gas chromatographic (GC)-mass spectrometric (MS) detection of amphetamine, methamphetamine, methylendioxyamphetamine, methylendioxymethamphetamine, methylendioxyethylamphetamine, methylendioxyphenylbutanamine, and methylmethylendioxyphenylbutanamine in human hair samples. Ten milligrams of hair is washed with deionized water, petroleum ether, and dichloromethane. After the addition of deuterated internal standards the sample is hydrolyzed with sodium hydroxide and directly submitted to HS-SPME. After the absorption of analytes for an on-fiber derivatization procedure the fiber is directly placed into the HS of a second vial containing N-methyl-bis(trifluoroacetamide) before GC-MS analysis. The limits of detection are determined between 0.01 and 0.17 ng/mg. Absolute analyte recoveries are in the range between 0.3% and 7.5%. Linearity is proven over a range from 0.1 to 50 ng/mg with coefficients of correlation from 0.998 to 1. In comparison with conventional methods of hair analysis, this fully automated HS-SPME-GC-MS procedure is substantially faster and easier to perform without using solvents. It uses minimal sample amounts and has the same degree of sensitivity and reproducibility.