Stored  Standard         Standard Peaks Contaminant Peaks Derivatized Underivatized Underivatized Unknown 7-ketoa 7-keto tms ether 7-keto 7-keto 3,5-7-oneb     19-OHc 19-OH tms ether     19-OH Related Triold Triol tms ether     Triol Related a7-ketocholesterol, b7-keto cholesta-3,5-dien-7-one, c19-hydroxycholesterol and dcholestane-3β-5α,6β-triol

Table 1: Peaks observed from the original standards after storage and derivatization.