Stereoselective analysis of ephedrine and its stereoisomers as impurities and/or by-products in seized methamphetamine by supercritical fluid chromatography/tandem mass spectrometry. (January 2021)

• Record Type: Journal Article
• Authors: Segawa, Hiroki; Okada, Yuki; Yamamuro, Tadashi; Kuwayama, Kenji; Tsujikawa, Kenji; Kanamori, Tatsuyuki; Iwata, Yuko T.
• Is Part Of: Forensic science international. Volume 318(2021)
• Publication Date: 2021-01
• Subjects: Supercritical fluid chromatography -- Stereoisomer -- Methamphetamine profiling -- Ephedrine; Medical jurisprudence -- Periodicals; Chemistry, Forensic -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Chimie légale -- Périodiques; Gerechtelijke geneeskunde; Gerechtelijke chemie; Gerechtelijke psychiatrie; Chemistry, Forensic; Medical jurisprudence; Electronic journals; Periodicals; Electronic journals; 614.1
• DOI: 10.1016/j.forsciint.2020.110591
• Languages: English
• ISSNs: 0379-0738

Abstract

Graphical abstract: Highlights: Chiral SFC method for ephedrine and its stereoisomers was developed. The method was suitable for crystalline methamphetamine including ephedrines. Fast analysis (11 min) with baseline separation was achieved. Unsupervised multivariate analysis objectively classified seized methamphetamine. Abstract: In forensic science, drug profiling is clarifying the identity of seized drugs of abuse based on their physicochemical properties and it is applied to various drugs, including crystalline methamphetamine. Impurity analysis is particularly important in drug profiling because the impurities can be a measure for speculating how the methamphetamine was synthesized in the clandestine laboratories. However, developments in scientific techniques have allowed the synthesis of high-purity, homogeneous crystalline methamphetamine, and thus new techniques to characterize methamphetamine are needed. In this study, we developed a method for chiral separation of ephedrine and its stereoisomers by supercritical fluid chromatography. Ephedrine is a common starting compound for methamphetamine synthesis. It possesses two chiral center carbon atoms and has four stereoisomers, (1 R, 2 S )–(−)–ephedrine, (1 S, 2 R )–(+)–ephedrine, (1 S, 2 S )–(+)–pseudoephedrine, and (1 R, 2 R )–(−)–pseudoephedrine. Because the stereostructure of ephedrines contained in methamphetamine seizure reflects the starting materials and the synthetic pathways, the stereoisomer ratio will provide additional information for drug profiling. The developed method achieved rapid separation of four isomers in about 11 min with low limits of detection (1 pg on column). Due to a switching valve connecting a chromatograph to a mass spectrometer, dense methamphetamine sample solutions containing small amount of ephedrines could be analyzed directly with a simple pre-treatment. Using multivariate analysis, 44 real samples were objectively grouped based on stereoisomer ratio. Our method is expected to improve the profiling of crystalline methamphetamine.