Rapid GC-MS confirmation of urinary amphetamine and methamphetamine as their propylchloroformate derivatives.

Amphetamine and methamphetamine are extracted from 200 microL of urine into an organic solvent containing propylchloroformate. The amines immediately react to form propylcarbamate derivatives. The aqueous phase is removed, and a portion of the organic phase is analyzed by gas chromatography-mass spectrometry. Either the deuterated analogues or N-propylamphetamine internal standards give acceptable results. For day-to-day precision, coefficients of variation in the range of 6-10% are found. The method is linear to 10,000 ng/mL. Limits of quantitation and detection are 50 and 5 ng/mL, respectively, when using N-propylamphetamine as the internal standard. Extracts are stable at room temperature for at least 60 days. There is no interference from other amphetamine drugs.