Application of liquid chromatography–electrospray ionization mass spectrometry for study of steroid-converting enzymes

A high-performance liquid chromatography–atmospheric pressure ionization–electrospray ionization mass spectrometry (HPLC–API–ESI–MS) method was developed for the analysis of steroids in a study of steroid-converting enzymes. Separations ware done on a Zorbax Eclipse XDB-C18 column (eluted with a linear methanol–water–acetic acid gradient) and identification of the steroids involved was done by API–ESI–MS using positive ion mode and extracted ion analysis. The applicability of the present method for studying steroid metabolism was proven in assaying two steroid-converting enzymes (20β-hydroxysteroid dehydrogenase and 11β-hydroxysteroid dehydrogenase) in various biological samples (rat and chicken intestine, chicken oviduct).