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Certification of steroid carbon isotope ratios in a freeze‐dried human urine reference material
Author(s) -
Munton Ellaine,
Liu FongHa,
John Murby E.,
Brynn Hibbert D.
Publication year - 2012
Publication title -
drug testing and analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.065
H-Index - 54
eISSN - 1942-7611
pISSN - 1942-7603
DOI - 10.1002/dta.1366
Subject(s) - etiocholanolone , chromatography , epitestosterone , chemistry , androsterone , urine , pregnanediol , isotope ratio mass spectrometry , testosterone (patch) , gas chromatography , high performance liquid chromatography , certified reference materials , steroid , detection limit , biochemistry , endocrinology , medicine , hormone
An accurate method for the measurement of carbon isotope ratios of steroids in human urine has been developed at the National Measurement Institute, Australia (NMIA) for the certification of a freeze‐dried human urine reference material (CRM NMIA MX005). The method measures δ 13 C values by gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS) analysis following hydrolysis, solvent extraction and high performance liquid chromatography (HPLC) purification. Reference δ 13 C values for testosterone metabolites etiocholanolone, androsterone, and endogenous reference compounds (ERCs) 11β‐hydroxyandrosterone and pregnanediol were determined, as well as information δ 13 C values for testosterone, epitestosterone, 11‐oxoetiocholanolone, and a range of differences (Δ 13 C) between testosterone metabolites and ERCs. The measurement uncertainty was rigorously evaluated with expanded uncertainties for the reference δ 13 C values between 1.1 and 1.6 ‰ at the 95% coverage level. Copyright © 2012 John Wiley & Sons, Ltd.