[Isolation and quantification of nonsulfated and sulfated bile acids in the feces]

A method is described for the qualitative and quantitative analysis of non-sulphated and sulphated bile acids in faeces. After extraction and preliminary purification, the faecal bile acids are separated by liquid-gel-chromatography (DEAP-Sephadex LH20) into free, conjugated and sulphated bile acids; these are quantitated separately (after solvolysis and hydrolysis), and the individual bile acids are analysed by gas-liquid-chromatography. The validation both of the individual analysis steps and the overall procedure by adding bile acid standards to the faecal homogenates showed a good reproducibility and a reliable separation of non-sulphated and sulphated bile acids. Using the described method, the excretion of total faecal bile acids in 15 control subjects was 3.85 mg/g dry stool, consisting of 10.4% primary bile acids and 89.6% secondary bile acids. 92.9% of faecal bile acids were in the free form, only 2.7% in the conjugated form, and 4.4% as sulphated bile acids.