Liquid chromatography-tandem mass spectrometry determination of plasma 24S-hydroxycholesterol with chromatographic separation of 25-hydroxycholesterol.
Concentrations of circulating 24S-hydroxycholesterol (24SOHChol) are of interest as a practical measure of cholesterol efflux from the human brain. The current method of choice for 24SOHChol quantification is with gas chromatography-mass spectrometry (GC-MS). Liquid chromatography-mass spectrometry (LC-MS) methods to detect 24SOHChol have been described, but they lack rigorous high-performance liquid chromatography (HPLC) separation of a closely eluting isomeric oxysterol, 25-hydroxycholesterol. This is important because 25-hydroxycholesterol can be present in significant amounts and tandem mass spectrometry (MS/MS) cannot completely differentiate 24SOHChol. We describe an LC-MS method with rapid chromatographic separation of the oxysterols to permit accurate determination of plasma 24SOHChol. The availability of an LC-MS method offers advantages such as simplified sample work-up and analysis.
Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239, USA. debarber@OHSU.edu
Andrea E
AE
DeBarber
Dieter
D
Lütjohann
Louise
L
Merkens
Robert D
RD
Steiner
D002853:Chromatography, Liquid; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006888:Hydroxycholesterols / Q000097:blood* / Q000302:isolation & purification*; D008297:Male; D053719:Tandem Mass Spectrometry / Q000379:methods*
D006888:Hydroxycholesterols; C044563:24-hydroxycholesterol; C007997:25-hydroxycholesterol