Determination of Amphetamine and Methamphetamine by Dispersive Liquid Phase Micro-extraction: A Novel Experimental Approach

Abstract

Background: A syringe to syringe dispersive liquid phase micro-extraction-floating organic drop was applied and used for the simultaneous extraction and pre-concentration of trace amounts of amphetamine (AMP) and methamphetamine (MAMP) in urine samples. The extracted analytes were determined by high performance liquid chromatography along with diode array detection. Methods: In this study, n-hexane was selected as the extraction solvent without the need to use dispersive solvent. The analytical parameters affecting the micro-extraction efficiency, including pH of sample solution, extraction solvent volume, the cycles of extraction and time of centrifugation were investigated and optimized by screening and optimization experimental design methods.  Results: Underoptimal conditions, the calibration curve had a linear range of 2-100 μg/L with the determination coefficient of R2=99.8 and R2=99.6 for AMP and MAMP, respectively. The limit of detection was 2 μg/L for AMP and MAMP, and the enrichment factor was 75 and 68 for AMP and MAMP, respectively.  Conclusion: This method is very simple, rapid and has been successfully used for pre-concentration and measurement of the analytes in urine samples, which is important to forensic studies.