Size exclusion chromatography for extraction of serum bile acids

A major problem in the measurement of serum bile acids is their quantitative extraction from the high molecular protein matrix. In our hands, the standard techniques of adsorption and reversed-phase chromatography have yielded incomplete recovery for different bile acids (33-93%) and poor reproducibility. In contrast, with the novel extraction procedure of size exclusion chromatography, recovery was nearly quantitative (75-104%) and reproducibility was satisfactory. The described method allowed for a reliable determination of serum bile acids in healthy subjects and patients with liver cirrhosis. We conclude that size exclusion chromatography for serum bile acid extraction is more reliable than alternative techniques, because the separation by size is independent of solubility, charge, and polarity.