Two-side slug-flow microextraction coupled with ion mobility spectrometry for fast quantification of amphetamine and methamphetamine in human urine

Abstract

In this study, first time a novel slug-flow microextraction (SFME) procedure named two-side SFME was developed and followed by ion mobility spectrometry equipped with corona discharge source (CD-IMS) for quantification of two abused drugs (amphetamine (AM) and methamphetamine (ME)) in urine samples. Regarding technique workflow, the organic extraction solvent (10 μL) was sandwiched between two portions of aqueous sample solution (the volume of each portion of sample solution was 5 μL) into a disposable glass capillary tube. The extraction of analytes was performed via the slug flows induced by the movements of the three liquids, which was conducted by tilting the glass capillary tube for several cycles. Finally, the extraction solvent was collected by a microsyringe and then injected (5 μL) into the CD-IMS. The effects of the effective parameters, including type of extraction solvent, number of tilting the glass capillary tube, and concentration of salt in sample solution were investigated. Under the optimized extraction condition (organic solvent: toluene; number of tilting the glass capillary tube: 10 times; concentration of salt: 5% (w/v)), the proposed two-side SFME/CD-IMS provided good linearity with coefficients of determination ≥0.993 over a concentration range of 25.0–2000.0 ng mL−1. Accordingly, acceptable limits of detection (S/N = 3) were 10.0 and 2.5 ng m‌‌L−1 for AM and ME, respectively. Furthermore, acceptable recoveries were ≥ 81.5, and ≥ 88.0% for AM and ME in a human urine sample, respectively, while repeatability and reproducibility ranged from 6.7 to 14.7% (n = 3).