Simultaneous derivatization and extraction of amphetamine and methamphetamine using dispersive liquid–liquid microextraction prior to their analysis using GC-FID in creatine supplements

This study was focused on the development of a sensitive, reliable, and efficient extraction procedure for the determination of amphetamine and methamphetamine utilized in the adulteration of creatine sports supplements. The separation and detection of the analytes were conducted using the gas chromatography-flame ionization detection method. In this study, the analytes were extracted from a supplement powder into a proper solvent by sonication. Then, the extract was mixed with butyl chloroformate to obtain their butylated derivatives and then concentrated by a dispersive liquid–liquid microextraction procedure. The method was performed in a short time. Under optimized extraction conditions, a linear range of 2.01–500 ng g−1 was obtained by a coefficient of determination ≥0.996. Low detection (0.22 ng g−1 and 0.61 ng g−1 for amphetamine and methamphetamine, respectively) and quantification (0.73 ng g−1 and 2.01 ng g−1 for amphetamine and methamphetamine, respectively) limits, good precision (relative standard deviations ≤8.2%), and high extraction recoveries (79% and 86% for amphetamine and methamphetamine, respectively) were achieved. The usefulness of the method in the analysis of the target compounds was confirmed by studying the matrix effect and analysis of the analytes in different real samples.