Development and validation of LC-ESI-MS/MS methods for quantification of 27 free and conjugated estrogen-related metabolites

Breast Cancer: Targeting of Steroid Hormones in Cancerogenesis and Diagnostics

“…Quantification of metabolites by the proposed method included parent estrogens, hydroxylated and methylated forms, metabolites of the 16α-hydroxyestrogen pathway, sulfate and glucuronide conjugated forms, precursors and related steroid hormone. The analysis required purification of the sample by a multi-step solid phase extraction procedure and derivatization of the metabolites by dansylation [93].…”

Simultaneous measurement of free and conjugated estrogens in surface water using capillary liquid chromatography tandem mass spectrometry

“…It was consistent with the chromatographic profiles reported in previous methods for measurement of both free and conjugated estrogens, wherein up to 45 min gradient was used for each injection. 28,63,65,[71][72][73] Though the C18 column did not allow complete baseline separation of the chosen compounds, especially for E2-DMIS and EE2-DMIS as well as E1-3S and E2-3S, they could be differentiated by mass spectrometric signal by the different m/z values of respective precursor ion and additionally by their specific fragmentation pathway upon MS 2 fragmentation of their precursor ions.…”

Mass spectrometry: Future opportunities for profiling and imaging steroids and steroid metabolites

“…Although the resolving power of LC is not as good as GC, ongoing improvements in LC technology are enabling multi-steroid profiling, albeit some steroids having poorer sensitivity and isomer separation remains challenging [20,21]. A further benefit of LC over GC is the ability to include conjugates in the analyte profile [22]. Moreover steroids are now an integral part of metabolomics screens [23] e.g.…”

“…Although sensitivity improves with instrument advances, derivatisation combined with LC to improve ionisation remains beneficial for ultimate sensitivity [22,27,28]. Derivatives append to specific chemicals groups, such as ketones or hydroxyls, and there is now increased interest in combining measurements of derivatised and underivatised steroids (e.g.…”

“…Derivatives append to specific chemicals groups, such as ketones or hydroxyls, and there is now increased interest in combining measurements of derivatised and underivatised steroids (e.g. estrogens and glucocorticoids respectively [29]), or derivatised steroids with conjugates [22], or parallel [30] derivatisation of two distinct chemical groups e all these approaches widen analytical profiles. Judicious use of mobile phase additives is gaining popularity to enhance sensitivity including stable lithium adducts [31] avoiding dehydration, and ammonium fluoride [32] which allows positive-negative switching and hence combined analysis of "negative"-estrogens and aldosterone -and "positive "steroids -glucocorticoid progestogens and androgens.…”