Results 111 to 120 of about 3,507,248 (152)

A simplified procedure for GC/C/IRMS analysis of underivatized 19-norandrosterone in urine following HPLC purification

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, Francesco Botre
exaly   +6 more sources

Doping in sport: 3. Metabolic conversion of oral norethisterone to urinary 19-norandrosterone

Steroids, 2009
The detection of 19 norandrosterone (19-NA) in a competitor's urine sample is taken as prima facie evidence of administration of nandrolone or other 19-norsteroid but a potential problem is that administration of norethisterone, a progestogen used for menstrual disorders and for hormonal contraception, also results in the excretion of 19-NA that can ...
Walker, Christopher J., Cowan, David A., James, Vivian H. T., Lau, Joanne C. Y., Kicman, Andrew T.   +4 more
exaly   +5 more sources

Doping in sport—1. Excretion of 19-norandrosterone by healthy women, including those using contraceptives containing norethisterone

Steroids, 2009
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.
Walker, Christopher J., Cowan, David A., James, Vivian H. T., Lau, Joanne C. Y., Kicman, Andrew T.   +4 more
exaly   +5 more sources

Direct detection and quantification of 19-norandrosterone sulfate in human urine by liquid chromatography-linear ion trap mass spectrometry

Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences, 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, Pierre-Edouard Sottas
exaly   +4 more sources

Determination of the Origin of 19-Norandrosterone in Urine by Gas Chromatography–Isotope-Ratio Mass Spectrometry for Doping Control

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, T. G. Sobolevskii, M. A. Dikunets   +2 more
exaly   +3 more sources

δ¹³C values of urinary 19‐norandrosterone in antidoping samples and potential for adverse findings from boar offal consumption

Drug Testing and Analysis, 2023
Abstract19‐Norandrosterone (19NA) is the preferred urinary target compound to identify doping with nandrolone or related 19‐norsteroids. At concentrations between 2.5 and 15 ng/mL, isotope ratio mass spectrometry (IRMS) is required to establish exogenous origin of urinary 19NA.
Vinod S. Nair, John D. Howa, Matthew S. Morrison, Lacey Beggs, Thane Campbell, Matthew Fedoruk, Brian Ahrens, Daniel Eichner   +7 more
openaire   +3 more sources

Application of online two‐dimensional high‐performance liquid chromatography as purification procedure to determine the origin of 19‐norandrosterone in urine by gas chromatography–combustion–isotope ratio mass spectrometry

Drug Testing and Analysis, 2020
Abstract19‐Norandrosterone (19‐NA) is the main metabolite of nandrolone and/or its precursors, which can be found naturally in human urine in trace amount. Gas chromatography–combustion–isotope ratio mass spectrometry (GC–C–IRMS) confirmation procedure can be used to identify a potential exogenous origin of 19‐NA in urine sample.
Chao Wen, Tianshuo Zhu, Jingzhu Wang, Xin Liu, Shan Wang, Yinong Zhang   +5 more
openaire   +3 more sources

Detecting the abuse of 19‐norsteroids in doping controls: A new gas chromatography coupled to isotope ratio mass spectrometry method for the analysis of 19‐norandrosterone and 19‐noretiocholanolone

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, Cristiana Colamonici, Davide Curcio, Francesco Botrè, Xavier de la Torre   +4 more
openaire   +4 more sources

Profiling of 19-norandrosterone sulfate and glucuronide in human urine: Implications in athlete's drug testing

Steroids, 2009
19-Norandrosterone (19-NA) as its glucuronide derivative is the target metabolite in anti-doping testing to reveal an abuse of nandrolone or nandrolone prohormone. To provide further evidence of a doping with these steroids, the sulfoconjugate form of 19-norandrosterone in human urine might be monitored as well.
Emmanuel Strahm
exaly   +4 more sources

Urinary 19‐norandrosterone purification by immunoaffinity chromatography: application to gas chromatography/combustion/isotope ratio mass spectrometric analysis

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
M C, Desroches, J C, Mathurin, Y, Richard, P, Delahaut, J, de Ceaurriz   +4 more
openaire   +3 more sources