title: Identification of Isomeric Ephedrines by Cold Ion UV Spectroscopy: Toward Practical Implementation.
abstract: Ephedrine and pseudoephedrine are stimulant drugs whose use is prohibited in athletic competition by the World Anti-Doping Agency (WADA) at very different threshold doping violation concentrations. We use a recently developed universal approach that integrates UV photofragmentation spectroscopy of cold ions with Orbitrap mass spectrometry (MS) for highly selective and highly sensitive identification of these diastereomers. Both species can be selectively detected at a solution concentration of a few tens of ng/mL, which is almost 3 orders of magnitude lower than the threshold concentration required by WADA. Relative concentrations of the isomers in solutions have been determined with the standard deviation of 3.1%, when the ions were cooled in an ion trap maintained at T = 6 K. Considering practical implementation of the method, we evaluated its performance for a simplified instrumentation. At an affordable elevated temperature of ∼70 K and with a low-maintenance midbandwidth optical parametric oscillator, a few second measurement should yield nearly the same selectivity and only ten times lower sensitivity than with the current research grade instrument.
authors.affiliation: Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kopysov
authors.affiliation: Thermo Fisher Scientific , Hanna-Kunath Str. 11, 28199 Bremen, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Makarov
authors.affiliation: Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland.
authors.forename: Oleg V
authors.identifier: 0000-0001-8867-3434
authors.initials: OV
authors.lastname: Boyarkin
mesh_terms: D003080:Cold Temperature; D004300:Doping in Sports; D004809:Ephedrine / Q000032:analysis* / Q000737:chemistry*; D007536:Isomerism; D013058:Mass Spectrometry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*
chemical_list: D004809:Ephedrine