Carbon Isotope Ratio Analysis of Steroids by High-Temperature Liquid Chromatography-Isotope Ratio Mass Spectrometry

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• 作者：Lijun Zhang ; Mario Thevis ; Thomas Piper ; Maik A. Jochmann ; J. Benjamin Wolbert ; Dorothea M. Kujawinski ; Steffen Wiese ; Thorsten Teutenberg ; Torsten C. Schmidt
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：March 4, 2014
• 年：2014
• 卷：86
• 期：5
• 页码：2297-2302
• 全文大小：277K
• 年卷期：v.86,no.5(March 4, 2014)
• ISSN：1520-6882

文摘

Generally, compound-specific isotope analysis of steroids is carried out by gas chromatography combined with isotope ratio mass spectrometry. Thus, a derivatization of the steroids prior to the measurement is compulsory, and a correction of the isotopic data is often necessary. To overcome this limitation, we present a new approach of high-temperature liquid chromatography coupled with photodiode array detection and isotope ratio mass spectrometry (HT-LC/PDA/IRMS) for the carbon isotope ratio analysis of unconjugated steroids. A steroid mixture containing 19-norandrosterone, testosterone, epitestosterone, androsterone, and 5尾-pregnane-3伪,17伪,20伪-triol was fully separated on a C₄ column under high-temperature elution with water as the sole eluent. The accuracy for isotope analysis (卤0.5 鈥? was around 20 渭g g^鈥? for testosterone, epitestosterone (79 ng steroid absolute on column), and 30 渭g g^鈥? for 19-norandrosterone, androsterone, and 5尾-pregnane-3伪,17伪,20伪-triol (119 ng steroid absolute on column). The applicability of the method was tested by measuring a pharmaceutical gel containing testosterone. With this work, the scope of LC/IRMS applications has been extended to nonpolar compounds.