Automated headspace solid-phase dynamic extraction for the determination of amphetamines and synthetic designer drugs in hair samples

The technique of automated headspace solid-phase dynamic extraction (SPDE) coupled with gas chromatography-mass spectrometry was evaluated for the determination of amphetamines and synthetic designer drugs in hair samples. Headspace SPIDE is a novel method for the solventless extraction of organic compounds in aqueous samples. In a so-called inside needle capillary absorption trap a hollow needle with an internal coating of polydimethylsiloxane is used as extraction and preconcentration medium. Sampling is per-formed on the solution headspace by passing the gas through the device actively by a syringe, Analytes present in the sample are sorbed onto the deposited stationary phase, The syringe needle is placed into the injection port of a GC and rapid heating of the metal needle induces the desorption of analytes, For the determination of amphetamine, methamphetamine, 3,4-methylendioxyamphetamine (MDA), 3,4-methylendioxymethamphetamine, 3,4-methylendioxyethylamphetamine (MDEA), 3,4-methylendioxyphenyl-2-butanamine and N-methyl-1-(3,4-methylendioxyphenyl)-2-butanamine in human hair samples, 10 mg of hair were hydrolysed with sodium hydroxide, After absorption of analytes for an on-coating derivatization procedure the SPIDE needle was directly placed into the headspace of a second vial containing N-methyl-bis(trifluoroacetamide). A validation procedure revealed absolute analyte recoveries between 10.2 and 16.7%. Linearity was obtained from 0.1 to 20 ng/mg with coefficients of correlation between 0.992 and 0.999. Intra- and inter-day precision were determined at two different concentrations and resulted in ranges between 1.4 and 4.1% (intra-day) and 4.2-14.6% (inter-day). Limits of detection between 0.03 ng/mg (NIDA) and 0.19 ng/mg (MDEA) were achieved. Results indicated that SPIDE is a rapid and sensitive method for the analysis of biological samples. Compared to solid-phase microextraction we found a higher extraction rate coupled with a faster automated operation. (C) 2002 Elsevier Science B.V. All rights reserved.