Quantitative determination of fecal bile acids as their methyl ether methyl esters by the repetitive scan technique

Quantification of bile acids has been carried out by selected ion monitoring and by repetitive scanning. The latter method has been explored critically and found to be very suitable. A 24 h collection of feces was submitted to Soxhlet extraction. The extract was purified on Servachrom XAD-2, and separated into sulfated and non-sulfated fractions over DEAP-Sephadex-LH20. Conjugated and sulfated bile acids were enzymatically deconjugated and desulfated prior to permethylation. Deuterated bile acid derivatives were added as external standards and an aliquot was injected onto a capillary column of SE-52. The reconstructed chromatogram traces of specific ions were integrated to quantify known bile acids. Spectra of all metabolites were available for identification purposes simultaneously.