Comparison of Supported Liquid Extraction and Solid Phase Extraction for Methamphetamine in Urine

Abstract

Incorporating forensic applications into chemical education serves as an effective strategy for engaging college students and equipping them with the skills necessary to become valuable in the workforce in relevant fields. For instance, learning how to extract controlled substances from biological specimens in a laboratory course is essential for students pursuing a career in forensic toxicology. This laboratory experiment was designed to teach junior or senior-level undergraduate students two commonly used extraction techniques, supported liquid extraction (SLE) and solid phase extraction (SPE), for extracting methamphetamine (MA) from MA-spiked urine, with detection and quantitation via gas chromatography–mass spectrometry (GC-MS). Specifically, the performance of SLE was compared with that of the mixed mode nonpolar/cation exchange SPE, and the effect of different extraction conditions on the recovery efficiencies was discussed for both techniques. Furthermore, students were introduced to key quantitative concepts, such as accuracy, precision, controls, coefficient of determination (R²), and coefficient of variation (CV %), etc., all of which are critical for method validation and ensuring the reliability of analytical results. The primary goal of this laboratory exercise was to deepen students’ understanding of the fundamental principles of these extraction methods while providing hands-on experience in analyzing an illicit drug in a biological matrix.