Method development and validation of six bile acids for regulated bioanalysis: improving selectivity and sensitivity

Background: Quantification of bile acids using LC–MS has previously been very challenging on triple quadrupole MS systems due to the absence of a primary fragment ion for unconjugated bile acids. Results: A LC–high-resolution/accurate mass MS method for the analysis of six bile acids (cholic acid, chenodeoxycholic acid, taurocholic acid, deoxycholic acid, lithocholic acid and ursodeoxycholic acid) was developed and successfully validated. The method includes a single extraction and a single injection with all analytes separated using target-selected ion monitoring (SIM) mode in two periods with a resolution of 70,000 and 140,000, respectively. Conclusion: This is the first LC–high-resolution/accurate mass assay fully validated to quantify six bile acids for regulated bioanalysis.