title: LC-MS-MS analysis of dietary supplements for N-ethyl-α-ethyl-phenethylamine (ETH), N, N-diethylphenethylamine and phenethylamine.
abstract: There has been a recent rise in the number of cases of athletes being banned from competition because of positive tests for prohibited substances in their biological specimens. Most of these substances are on the World Anti-Doping Agency (WADA) prohibited list, while others are not specifically named on the list. N-Ethyl-α-ethyl-phenethylamine (ETH), a derivative of phenethylamine (PEA), is one of these unlisted substances and shares chemical and biological effects to the amphetamines, which are listed on the WADA prohibited substances list. It is classified as Category 6B stimulant on the list. This study was directed toward the development of an liquid chromatography tandem mass spectrometry (LC-MS-MS) method for the analysis of ETH in performance-enhancing dietary supplement. A standard was prepared and confirmed by spectroscopic analysis, which was then used to develop the analytical procedure. The procedure was validated and found to have an limit of detection of 2.5 ng/mL, limit of quantification of 5 ng/mL and upper limit of linearity of 500 ng/mL, with within-day variability at the 10-ng/mL level range of 3.88-7.89% (n = 6) and 1.39-3.36% (n = 6) for the 100-ng/mL level. The day-to-day variability was 9.8% for the low control and 3.1% for the high control. The method was used to analyze a variety of dietary supplements for ETH as well as PEA and its N, N-diethyl derivative (NDP).
authors.affiliation: 1 ElSohly Laboratories, Inc. (ELI) and Phytochemical Services, Incorporated (PSI), 5 Industrial Park Drive, Oxford, MS 38655, USA.
authors.forename: Mahmoud A
authors.initials: MA
authors.lastname: ElSohly
authors.forename: Waseem
authors.initials: W
authors.lastname: Gul
mesh_terms: D002082:Butylamines / Q000032:analysis*; D002138:Calibration; D002853:Chromatography, Liquid / Q000592:standards; D019587:Dietary Supplements / Q000032:analysis*; D004300:Doping in Sports; D006801:Humans; D057230:Limit of Detection; D009682:Magnetic Resonance Spectroscopy; D058573:Performance-Enhancing Substances / Q000032:analysis*; D010627:Phenethylamines / Q000032:analysis*; D011237:Predictive Value of Tests; D012015:Reference Standards; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000379:methods* / Q000592:standards; D053719:Tandem Mass Spectrometry / Q000592:standards
chemical_list: D002082:Butylamines; D058573:Performance-Enhancing Substances; D010627:Phenethylamines; C029261:phenethylamine; C000592346:N-ethyl-alpha-ethyl-phenethylamine