Abstract
A sample preparation method based on modified Quick, Easy, Cheap Effective, Rugged, and Safe (QuEChERS) and GC-MS method was developed and validated for identification and quantification of amphetamine (AP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), and 3,4-methylenedioxymethamphetamine (MDMA) in human urine. Several derivatization parameters such as derivatization temperature, time, and volume of derivatizing agent were optimized. dSPE parameters were optimized. Under the optimized conditions, the method was validated with respect to selectivity, linearity, limits of detection and quantification, precision, accuracy, and recoveries. Linearity was obtained in the concentration range of 50-1200 ng/mL for all the drugs. The intra- and inter-day precision and accuracy were acceptable. The RSD values ranging from 0.08 to 3.43% and 0.23% to 3.0% for intra- and inter-day precision were obtained, respectively. Accuracy was within the required limits (+/- 15% and +/- 20% at LOQ) for all analytes at three concentrations studied. Analyte recoveries that ranged from 87.8 to 95% were obtained. These figures resulted within the best recovery percentages as comparing with the previous studies. The method was successfully applied to the routine work of the Sudanese Forensic laboratories to detect and quantify the AP, MA, MDA, and MDMA in urine samples.