Artifacts in the GC–MS profiling of underivatized methamphetamine hydrochloride

When underivatized methamphetamine hydrochloride (MA·HCl) in methanol is subjected to the instant gas chromatographic–mass spectrometric (GC–MS) profiling with old inlet liners at temperatures above 200 °C, appreciable amounts of N,N-dimethylamphetamine (DMA) and amphetamine (AP) are produced. The presence of these two artifacts is attributed to the N-demethylation and N-methylation reactions of MA as well as methyl group exchange with methanol. These artifacts are only produced in old injection port liners and at elevated temperatures. The formation of artifacts is proportional to concentration of MA·HCl. It is suggested that special cautions and measures be undertaken to prevent artifacts.