Trace-level determination of eight cholesterol oxidation products in human plasma by dispersive liquid-liquid microextraction and ultra-performance liquid chromatography-tandem mass spectrometry

摘要

7-Hydroxy cholesterol (7-OHC), 25-hydroxy cholesterol (25-OHC), 27-hydroxy cholesterol (27-OHC), 4-hydroxy cholesterol (4-OHC), 7-hydroxy-4-cholesten-3-one (7-C4), 5-cholestane-3, 7, 12-triol (5-Triol), cholic acid (CA), and chenodeoxycholic acid (CDCA) are known biomarkers of neurodegenerative diseases. A method for their simultaneous determination in human plasma has been optimized using dispersive liquid-liquid microextraction and ultra-performance liquid chromatography-tandem mass spectrometry. The limits of quantification of the target compounds were in the range of 0.3-3.3 mu g/L. The precision achieved by this method was less than 13.4% for intraday and interday analyses. The proposed method was used to analyze eight cholesterol oxidation products in 30 human plasma samples. The analytical results were in a concentration range of 1.6-87.4 mu g/L for 7-OHC, 6.3-58.2 mu g/L for 25-OHC, 12.1-98.5 mu g/L for 27-OHC, 5.7-64.8 mu g/L for 4-OHC, 1.5-124.1 mu g/L for 7-C4, 0.5-16.5 mu g/L for 5-Triol, 13.1-245 mu g/L for CA, and 19.6-487 mu g/L for CDCA in the samples. The method may be used for the analysis of biomarkers of neurodegenerative diseases.