Determination of impurities in illicit methamphetamine seized in Korea and Japan

Impurities produced during synthesis of methamphetamine (MA) show different patterns under various synthetic conditions. Valuable information on the origins and smuggling routes can be obtained by using impurities as chemical fingerprints. We have detected more than 100 compounds from 436 MA samples seized in Korea by gas chromatography–flame ionization detector and gas chromatography–mass spectrometer, among which 31 impurities and three additives were identified. Twenty-six impurity peaks including unknowns were selected as the indicators of similarity, and were used as variables for cluster analysis. Cluster analysis result showed that part of the MA samples seized in Japan might have the same origin as those seized in Korea. It means that broad-based cooperation is necessary for efficient regulation of MA. Synthetic trends of the MA seizures of Korea were monitored by cluster analysis with 16 MA samples synthesized by three different methods in the previous work. We could find comparable changes of synthetic trends, which might have been influenced by domestic regulations and international situations.