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

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 δ13C and δ15N values, they could be identified from the δ2H values. The low deuterium content of biosynthetic ephedrines (δ2H: −193 to −151‰) allows a clear distinction from synthetic ephedrines (δ2H: −73 to −30‰), semisynthetic ephedrines derived from pyruvic acid (δ2H: +75 to +148‰) and semisynthetic ephedrines derived from molasses (δ2H: −74 to +243‰). The wide range of δ2H values of semisynthetic ephedrines is therefore very useful for the detailed classification of ephedrines, in combination with the measurement of δ13C and δ15N 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.