Compound name Major ions Minorions Detection limit (ng) Cholesterol 386, 275 301, 368, 353 0.70 Cholestanetriol 402, 384 369, 303,331 1.50 Cholesterol-5β,6β-epoxide 402 384, 369, 275 1.20 Cholesterol-7-hydroperoxide 400 367, 382, 287 0.75 7-Ketocholesterol 400 367, 382, 287 0.75 5α-Cholestane 372 - - 7a-Hydroxycholesterol 384 402, 369 1.0 Cholesta-3，5-diene-7-one 174 382, 367, 398 1.0 Cholesterol-5α,6α-epoxide 402 384, 369, 275 1.20 25-Hydroxycholesterol 402 400 1.0

Table 1: The principal ions monitored for analysis of cholesterol oxides by HPLCMS with the particle-beam interface.