Rapid extraction and determination of amphetamines in human urine samples using dispersive liquid–liquid microextraction and solidification of floating organic drop followed by high performance liquid chromatography

• Combination of DLLME-SFO and HPLC–UV was used for the determination of amphetamines in human urine.
• The new method avoided using high density and toxic extraction solvents.
• Linear calibration was above 10–3000 μg l−1 and limit of detections was in the range of 2–8 μg l−1.

A novel, rapid, simple and sensitive dispersive liquid–liquid microextraction method based on the solidification of floating organic drop (DLLME-SFO) combined with high-performance liquid chromatography–ultraviolet detection (HPLC–UV) was used to determine amphetamine and methamphetamine in urine samples. The factors affecting the extraction efficiency of DLLME-SFO such as the kind and volume of the extraction and the disperser solvents, effect of concentration of K2CO3 and extraction time were investigated and the optimal extraction conditions were established. Under the optimum conditions (extraction solvent: 30.0 μl 1-undecanol; disperser solvent: 300 μl acetonitrile; buffer concentration: 2% (w/v) K2CO3 and extraction time: 1 min), calibration curves are linear in the range of 10–3000 μg l−1 and limit of detections (LODs) are in the range of 2–8 μg l−1. The relative standard deviations (RSDs) for 100 μg l−1 of amphetamine and methamphetamine in diluted urine are in the range of 6.2–7.8% (n = 7). The method was successfully applied for the determination of amphetamine and methamphetamine in the actual urine samples. The relative recoveries of urine samples spiked with amphetamine and methamphetamine are 87.8–113.2%. The obtained results show that DLLME-SFO combined with HPLC–UV is a fast and simple method for the determination of amphetamine and methamphetamine in urine.

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