Simultaneous determination of amphetamine and related compounds in human urine using ultrasound-assisted emulsification microextraction and gas chromatography

Abstract

3,4-methylenedioxymethylamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxyethylamphetamine (MDEA) and 3,4-methylenedioxypropylamphetamine (MDPA) were extracted from human urine by using ultrasound-assisted emulsification microextraction (USAEME) method based on applying low density organic solvents followed by gas chromatographic analysis with flame ionization detection. Fourteen microliters of toluene was injected slowly into a 12 mL home-designed centrifuge glass vial containing a sample without salt addition that was located inside the ultrasonic water bath. The formed emulsion was centrifuged and 2 μL of separated toluene was injected into a gas chromatographic system equipped with a flame ionization detector (GC-FID) for analysis. In order to improve the extraction efficiency, experimental parameters affecting the extraction efficiency, including type and volume of extraction solvent, pH value of sample, extraction time and temperature were investigated. Under the optimal conditions, the linear dynamic range was in the range of 0.5–500 μg L⁻¹ for MDEA and MDPA and 1.0–500 μg L⁻¹ for MDA and MDMA with limits of detection (LODs) in the range of 0.2 to 0.4 μg L⁻¹. The results indicate that the developed method is rapid, accurate and sensitive and can be used for the simultaneous determination of MDA, MDMA, MDEA and MDPA in urine samples.