Direct detection and quantification of 19-norandrosterone sulfate in human urine by liquid chromatography-linear ion trap mass spectrometry.
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. The method involved a quaternary amine SPE protocol and subsequently injection of the extract onto an analytical column (Uptisphere ODB, 150 mm x 3.0 mm, 5 microm) for chromatographic separation and mass spectrometry detection in negative electrospray ionisation mode. The sulfoconjugate of 19-NA was identified in urine by comparison of mass spectra and retention time with a reference substance. The limit of detection (LOD) and lowest limit of quantification (LLOQ) of 19-NAS were of 40 pg/mL and 200 pg/mL, respectively. For a nominal concentration of 2 ng/mL, recovery (94%), intra-day precision (2.7%), intra-assay precision (6.6%) and inter-assay precision (14.3%) were determined. Finally, this analytical method was applied for quantifying the concentration of 19-NAS in doping samples, using calibration curves (0.2-20 ng/mL) and the standard-addition method. The results show the feasibility of applying this LC-MS/MS assay as a complementary tool to detect misuse of nandrolone or nandrolone precursors.
Strahm
Emmanuel
E
Laboratoire Suisse d'Analyse du Dopage, Institut Universitaire de Médecine Légale, Chemin des Croisettes 22, 1066 Epalinges, Switzerland.
Saudan
Christophe
C
Sottas
Pierre-Edouard
PE
Mangin
Patrice
P
Saugy
Martial
M
D002853:Chromatography, Liquid / Q000379:methods*; D004962:Estranes / Q000652:urine*; D006801:Humans; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
D004962:Estranes; C036015:19-norandrosterone