A GC/MS method for the simultaneous analyses of different amphetamines and ephedrines in urine employing analytical-grade acetic anhydride/pyridine as derivatizing reagents was developed and validated. Solid-phase extraction was performed on the samples, which were then derivatizated and analyzed by GC/MS. The method showed a broad linear dynamic range (25-1000 ng mL-1 with R² > 0.99), high sensitivity (LODs of 0.0140 to 15.33 ng mL-1 and LOQs of 0.0466 to 51.10 ng mL-1), good precision (CV < 6% for intra- and inter-assays), and excellent extraction recovery (87 to 96%) for all the compounds studied. After validation, the method was applied in the analyses of real samples of human urine which were previously determined to contain at least one of such drugs. In all the samples, the amphetamines and ephedrines were promptly quantified, showing that the association of acetic anhydride and pyridine can be conveniently employed as a derivatizing agent.
stimulants; amphetamines; ephedrines; GC/MS; acetic anhydride/pyridine; urine analysis; derivatizing reagents
