Use of stable isotope ratios for profiling of industrial ephedrine samples: Application of hydrogen isotope ratios in combination with carbon and nitrogen

Abstract

The utility of hydrogen stable isotope ratio measurement by IR-MS for establishing the origin of ephedrine and pseudoephedrine (ephedrines), precursors of methamphetamine, was evaluated. There are two kinds of commercial semisynthetic ephedrines, one produced from molasses and the other from pyruvic acid. While the semisynthetic ephedrines derived from pyruvic acid cannot be discriminated from biosynthetic ephedrines and synthetic ephedrines based on δ 13C and δ 15N values, they could be identified from the δ 2H values. The low deuterium content of biosynthetic ephedrines (δ 2H: −193 to −151‰) allows a clear distinction from synthetic ephedrines (δ 2H: −73 to −30‰), semisynthetic ephedrines derived from pyruvic acid (δ 2H: +75 to +148‰) and semisynthetic ephedrines derived from molasses (δ 2H: −74 to +243‰). The wide range of δ 2H values of semisynthetic ephedrines is therefore very useful for the detailed classification of ephedrines, in combination with the measurement of δ 13C and δ 15N values as described in our previous work. This study was carried out on a limited number of samples reflecting the various routes of ephedrines manufacture. But it has become apparent that this stable-isotope analysis is an appropriate means by which to screen for manufacturing process of ephedrines. This approach should be useful for worldwide precursor control of methamphetamine.