Determination of Bile Acids in Rat Cecal Contents by LC–MS

Abstract

Bile acids are essential materials in the fatty acid cycle. Thus, understanding the metabolism of bile acids is significant. In this study, LC–MS was employed to analyze the composition and content of bile acids in rat cecal contents. Six individual bile acids were determined simultaneously. The mobile phase consisted of acetonitrile and 10 mmol L−1 of ammonium acetate solution. The flow rate was 0.2 mL min−1, and the total analysis time was 34 min. Under the developed conditions, all calibration curves for the six individual bile acids were achieved, and all correlation coefficients exceeded 0.99. Meanwhile, satisfactory results were obtained in the range of 50–500 µg g−1 for the six individual bile acids in the rat cecal contents. The LOD and LOQ of the bile acids were as low as 2.5 and 10 µg g−1 in the rat cecal contents, respectively, and the relative standard deviations of the peak area were within 1.25–2.01%. The dried residues after extraction were selected as the blank matrix. The overall recovery efficiencies of the bile acids in biological samples were increased to 97.2–103.2%. Therefore, the developed method can be used to quantify individual bile acids at extremely low levels in rat cecal contents.