Fig. 2: Improved separation of sterol isomers with derivatization and IM-MS.

a Overlay of the IM mobiligrams of underivatized and derivatized sterol isomers of etiocholanone and epiandrosterone. b The percentages of sterol isomers with significant CCS differences (≥2%) in the derivatized (n = 125) and underivatized (n = 163) groups. c The peak resolutions (RS) in LC separation (left), IM separation and LC-IM based two-dimensional separation (middle and right) for the sterol isomers of aldosterone and cortisone after derivatization. d The percentages of sterol isomers (n = 125) with peak resolutions larger than 1.0 in LC separation, IM separation, and LC-IM based two-dimensional separation.