Analysis of inorganic impurities in seized methamphetamine samples

Abstract Classification of seized methamphetamine by impurity profiling can provide very useful information on drug intelligence. In this report, the validity of inorganic impurity analysis in discriminating seized methamphetamine samples in Japan was investigated using inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS). Triplicate sampling was carried out on 17 methamphetamine samples seized in Japan. About 20 mg of methamphetamine was taken, and was dissolved in 20 ml of water. After the qualitative analysis, Ba, Sb, Pd, Sr, Br, Zn and Cu were determined by ICP-MS, and Na was determined by AAS. Among eight elements determined in this study, most cations showed large heterogeneity in their content. On the other hand, the contents of Na which is abundant in methamphetamine samples, showed relatively small intra-sample variation, and that of Br also showed good homogeneity. On the basis of the concentration of Br and Na, 17 seized methamphetamine samples were classified into five groups. Trace elements such as Tl, Hg, Au or Cs were qualitatively detected by ICP-MS. These elements can provide useful information to impurity profiling of seized methamphetamine, because these elements are characteristically present in each sample. Application of ICP-MS and AAS to the analysis of inorganic impurities can be helpful in giving additional information to the impurity profiling of seized methamphetamine by organic impurity analysis.