A review on structural elucidation of metabolites of environmental steroid hormones via liquid chromatography–mass spectrometry

Abstract This review covers liquid chromatography–mass spectrometry (LC-MS) strategies for structural elucidation of degradation and transformation products of environmental steroid hormones due to their estrogenic and/or androgenic effects on environmental living life. We focus on identification fundamentals of unknown metabolites rather than on target analysis. We discuss LC-MS capacities and overall MS-based steps for structural elucidation of unknown metabolites. Also summarized in the review are the fragmentation reactions and fragmentation pathways of protonated and deprotonated molecules of unknown compounds. We pay particular attention to versatile orthogonal techniques (e.g., isotopic labeling, hydrogen/deuterium exchange and model compound utilization) associated with MS and intelligent spectral interpretation strategies used in literature for structural elucidation of steroid hormone metabolites. We provide up-to-date applications of LC-MS on structural elucidation of biotic and abiotic transformation products of steroid hormones in environmental samples. Most of what is discussed in this review also applies to other emerging environmental contaminants.