Abstract: Objective · To develop a quantitative method of 7α-hydroxy-4-cholesten-3-one (C4), cholic acid (CA) and chenodeoxycholic acid (CDCA) in human plasma. Methods · After extraction of C4, CA and CDCA with acetonitrile plasma, they were quantified with standard curve correctedthe internal standards based on Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Results · The limits of detection (LOD) of C4, CA and CDCA were 0.16, 0.02 and 0.04 nmol/L respectively; All three metabolites had good linear relationships (correlation coefficients R2 were over than 0.998). The relative standard deviations (RSDs) of repeatabilities were below 3.0%. The RSDs of inter-day and intra-day precision were less than 6%, and the RSDs of stabilities at 4 °C were below 10% within 7 days. The average added recoveries of C4, CA and CDCA were 97.7%, 113.3% and 105.0%, respectively. Conclusion · This method is of high detective sensitivity, good precision and stability, which meets the quantitative requirements of plasma biological samples.

Key words: 7α-hydroxy-4-cholesten-3-one (C4), cholic acid (CA), chenodeoxycholic acid (CDCA), UPLC-MS/MS, quantification