Fig. 5.

LC-MS separation of GP-derivatised cholestenoic acids, monohydroxycholesterols and monohydroxycholestenones in plasma samples representative of the inborn errors of cholesterol metabolism ACOX2 deficiency and CTX. (A) RIC (564.3796 ± 5 ppm) for [M]⁺ ions corresponding to 7αH,3O-CA(25R/S) in NIST SRM 1950 plasma (upper panel), from a patient suffering from ACOX2 deficiency (central panel), and the RIC (567.3984 ± 5 ppm) corresponding to the [M]⁺ ion of [²H₃]7αH,3O-CA(25R/S) (lower panel). (B) RIC (569.4110 ± 5 ppm) for [M]⁺ ions corresponding to 3β,7α-diHCA(25R/S) + 7αH,3O-CA(25R/S) in NIST SRM 1950 plasma (upper panel), from a patient suffering from ACOX2 deficiency (central panel), and the RIC (572.4298 ± 5 ppm) corresponding to the [M]⁺ ion of [²H₃]7αH,3O-CA(25R/S) (lower panel). Samples in (A) have been treated with [²H₀]GP and those in (B) with [²H₅]GP. (C) RIC (539.4368 ± 5 ppm) for [M]⁺ ions corresponding to monohydroxycholesterols and monohydroxycholestenones in NIST SRM 1950 plasma (upper panel), from a sample from a patient suffering from CTX (central panel), and the RIC (546.4807 ± 5 ppm) corresponding to the [M]⁺ ion of [²H₇]24R/S-HC (lower panel). (D) RIC (564.3796 ± 5 ppm) for [M]⁺ ions corresponding to 7αH,3O-CA(25R/S) in NIST SRM 1950 plasma (upper panel), from a sample from a patient suffering from CTX (central panel), and the RIC (567.3984 ± 5 ppm) corresponding to the [M]⁺ ion of [²H₃]7αH,3O-CA(25R/S) (lower panel). Coloured dashed lines indicate the coincidence of oxysterols between chromatograms.