Chiral Analysis of Amphetamine and Methamphetamine in Urine by Liquid Chromatography-Tandem Mass Spectrometry Applying Mosher Derivatization

Methamphetamine (MA) and amphetamine (AM) are central nervous system doping agents, listed in the WADA Prohibited List, which in the past years showed the highest prevalence among all stimulants. Specifically, concerning these stimulants, it is essential to distinguish between d and l-isomers of AM and MA due to their distinction in illicit or legal nonprescription use. The main separation methods used for the urinary determination of MA and AM enantiomers are based on chromatographic procedures, such as gas chromatography after chiral derivatization or liquid chromatography (LC) applying chiral columns, followed by the mass spectrometer (MS) detection. The use of the optically pure reagent R-(-)-α-methoxy-α-(trifluoromethyl) phenylacetic acid chloride (R-MTPA-Cl – Mosher’s Reagent) allows the isomeric separation by both chromatographic procedures while preserving the isomeric composition of the substances. Therefore, in the present work, an LC-MS2 approach has been developed for AM and MA detection in urine after Mosher derivatization. The method was validated and can be used for the enantioselective confirmation of AM and MA for doping control purposes and forensic analysis in general, being useful for the distinction between the medicinal and illicit use of both stimulants.