Summary: | A sensitive and selective fiber for simultaneous analysis of three drugs of abuse (amphetamine, methamphetamine and ephedrine) in urine samples was explored using headspace solid phase microextraction and gas chromatography with flame ionization detection. Several parameters affecting extraction such as extraction time, extraction temperature, pH of solution and salt concentrations were investigated. Among five commercially available fibers, divinylbenzene/carboxen/ polydimethylsiloxane is the most sensitive and selective fiber at pH 10.0, extraction temperature at 80 C for 20 min and desorption temperature at 220 C for 2 min. Under the optimal conditions, the proposed solid phase microextraction method provided good linearity in the ranges 0.1-10 µg/ml for amphetamine and methamphetamine and 0.5-20 µg/ml for ephedrine. The detection limits for amphetamine, methamphetamine and ephedrine were 9, 3 and 30 ng/ml, respectively. The recoveries of three drugs in urine samples were exceeding 85%.
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