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Mass spectrometric characterization of efaproxiral (RSR13) and its implementation into doping controls using liquid chromatography–atmospheric pressure ionization‐tandem mass spectrometry
Author(s) -
Thevis Mario,
Krug Oliver,
Schänzer Wilhelm
Publication year - 2006
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.993
Subject(s) - chemistry , chromatography , direct electron ionization liquid chromatography–mass spectrometry interface , mass spectrometry , atmospheric pressure chemical ionization , tandem mass spectrometry , liquid chromatography–mass spectrometry , characterization (materials science) , atmospheric pressure , analytical chemistry (journal) , tandem , protein mass spectrometry , ionization , chemical ionization , ion , organic chemistry , nanotechnology , materials science , oceanography , composite material , geology
Efaproxiral (2‐[4‐[[(3,5‐dimethylanilino)carbonyl]methyl]phenoxyl]‐2‐methylpropionic acid, formerly referred to as RSR13) is prohibited in sports according to the World Anti‐Doping Agency (WADA). The drug as well as structurally related compounds and a stable isotope‐labeled derivative have been synthesized to elucidate the fragmentation pathway of efaproxiral, using electrospray ionization (ESI) and tandem mass spectrometry by employing a novel linear ion trap—orbitrap hybrid mass spectrometer—in positive and negative ionization modes. The elimination of 2‐methyl acrylic acid (−86 u) has been identified as a major fragmentation process in both charge states. Negative ionization and collision‐induced dissociation (CID) caused an additional release of carbon dioxide (−44 u), and positive ionization the loss of formic acid (−46 u). Efaproxiral was incorporated into an existing screening procedure for doping controls using solid‐phase extraction (SPE) followed by liquid chromatography‐tandem mass spectrometry, enabling a limit of detection of 2.5 ng/ml and interday precisions ranging from 7.9 to 13.0%. Copyright © 2006 John Wiley & Sons, Ltd.