Results 111 to 120 of about 357 (143)
Accreditation and Quality Assurance, 2007 An accurate and precise method for the determination of total 19-norandrosterone (19-NA), a major metabolite of nandrolone, in human urine was developed based on isotope dilution gas chromatography-high resolution mass spectrometry (ID GC-HRMS). The 19-NA glucuronide, together with deuterated 19-NA (d4-19-NA) (as the internal standard, IS), was ...
Wing‐Chi Cheng +4 more
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Steroids, 2008 19-Norandrosterone (19-NA) is the principal urinary metabolite of the anabolic steroid nandrolone and its prohormones. The administration of these 19-nor androgens is prohibited in sport by the World Anti-Doping Agency (WADA) but, even so, adverse findings for 19-NA continue to be commonly reported.
Christopher J. Walker +4 more
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Accreditation and Quality Assurance, 2007 The US National Institute of Standards and Technology (NIST) participated in an international interlaboratory study under the auspices of the Consultative Committee for Amount of Substance (CCQM) for the determination of 19-norandrosterone (19-NA) in urine, the principal metabolite of nandrolone and certain other synthetic testosterone substitutes ...
Susan S.-C. Tai +2 more
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Evidence for the presence of endogenous 19-norandrosterone in human urine
Journal of Chromatography B: Biomedical Sciences and Applications, 1999 In 1997, in the scope of antidoping control in sport, a not inconsiderable number of urine analysed by official laboratories revealed the presence of 19-nortestosterone (19-NT: 17beta-hydroxyestr-4-en-3-one) metabolites: 19-norandrosterone (19-NA: 3alpha-hydroxy-5alpha-estran-17-one) and 19-noretiocholanolone (19-NE: 3alpha-hydroxy-5beta-estran-17-one).
Bruno Le Bizec +3 more
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Journal of Analytical Chemistry, 2018 The most difficult task in antidoping control is the identification of compounds whose origin can be either endogenous or exogenous. This paper presents a procedure for determining the origin of 19-norandrosterone based on the extraction of target components from urine, their multistage purification by semipreparative HPLC, acetylation, and ...
I. I. Podolskiy +2 more
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Journal of Chromatography B, 2007 19-Norandrosterone sulfate (19-NAS) is the sulfoconjugated form of 19-norandrosterone (19-NA), the major metabolite of the steroid nandrolone. A sensitive and accurate liquid chromatography/tandem mass spectrometry (LC-MS/MS) assay was developed for the direct measurement of 19-NAS in human urine samples.
Emmanuel Strahm +4 more
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The appearance of urinary 19‐norandrosterone during pregnancy
European Journal of Sport Science, 2002 (2002). The appearance of urinary 19-norandrosterone during pregnancy. European Journal of Sport Science: Vol. 2, No. 2, pp. 1-7.
Ute Mareck‐engelke +3 more
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Steroids, 2011 Nandrolone and/or its precursors are included in the World Anti-doping Agency (WADA) list of forbidden substances and methods and as such their use is banned in sport. 19-Norandrosterone (19-NA) the main metabolite of these compounds can also be produced endogenously.
Xavier de la Torre +5 more
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Rapid Communications in Mass Spectrometry, 2002 Abstract The detection of exogenous 19‐norandrosterone (19‐NA) in urines was investigated by using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). 19‐NA is, for the first time to our knowledge, isolated from urinary matrix by specific immunoaffinity chomatography (IAC) before analysis. The sample preparation
Marie-Catherine Desroches +4 more
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Drug Testing and Analysis, 2020 AbstractThe detection of 19‐norsteroids abuse in doping controls currently relies on the determination of 19‐norandrosterone (19‐NA) by gas chromatography–tandem mass spectrometry (GC–MS/MS). An additional confirmatory analysis by gas chromatography coupled to isotope ratio mass spectrometry (GC‐C‐IRMS) is performed on samples showing 19‐NA ...
Loredana Iannella +4 more
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