%0 Journal Article %A Adhikari, Sarju %A Xia, Yu %D 2017 %T Thiyl Radical-Based Charge Tagging Enables Sterol Quantitation via Mass Spectrometry %U https://acs.figshare.com/articles/journal_contribution/Thiyl_Radical-Based_Charge_Tagging_Enables_Sterol_Quantitation_via_Mass_Spectrometry/5632570 %R 10.1021/acs.analchem.7b04080.s001 %2 https://acs.figshare.com/ndownloader/files/9809338 %K 44 Da %K vegetable oil %K Mass Spectrometry %K loss scan %K thiyl radicals %K charge derivatization method %K quantifying sterols %K B ring %K electrospray ionization-mass spectrometry %K flow microreactor %K Thiyl Radical-Based Charge Tagging Enables Sterol Quantitation %K TGA abstracts %K Thioglycolic acid %K allylic hydrogen %K carboxylic acid group %K ESI-MS %X Inspired by the high reactivity and specificity of thiyl radicals toward alkenes, we have developed a new charge derivatization method to enable fast and quantitative analysis of sterols via electrospray ionization-mass spectrometry (ESI-MS). Thioglycolic acid (TGA), a commercially available compound, has been established as a highly efficient tagging reagent. Initiated from photochemical reactions, the thiyl radical derived from TGA abstracts an allylic hydrogen in the B ring of sterols, forming a radical intermediate which rapidly recombines with a second thiyl radical to produce the final tagged product. Because of the incorporation of a carboxylic acid group, TGA tagging not only improves the limit of detection (sub-nM) for sterols but also facilitates their quantitation via characteristic 44 Da neutral loss scan. This radical based derivatization is fast (1 min) and efficient (>90% yield) when conducted in a flow microreactor. The analytical utility of thiyl radical charge tagging method has been demonstrated by quantifying sterols from human plasma and vegetable oil. %I ACS Publications