Measurement of human serum bile acids by gas–liquid chromatography

Abstract

Gas–liquid chromatography (GLC) has been used for the separation and quantification of the bile acids of normal and abnormal serum. Recovery of added bile acids from serum samples during the combined processes of extraction with an anion exchanger, hydrolytic cleavage of the conjugates, and purification by alumina chromatography of the bile acid methyl esters, was 60–85%. The main serum bile acids were identified as deoxycholic, chenodeoxycholic, and cholic acids by GLC of their methyl esters. partial trimethylsilyl ethers, and trifluoracetates. Quantification was most satisfactorily achieved with the trifluoracetates of the methyl esters on the stationary phase QF-1.Values for normal fasting subjects ranged from 0.03 to 0.23 mg/100 ml of serum. In two experiments the level rose from 0.04–0.06 to 0.18–0.32 mg/100 ml after a meal. In a number of patients with liver disease the serum bile acid levels were between 0.39 and 20.1 mg/100 ml. Deoxycholic acid was either absent or made up only a small percentage of the total bile acids in these patients. In two patients examined. 3 and 5% of the bile acids were unconjugated.