7β,12β-dihydroxy-5β-cholan-24-oic acid as an internal standard for quantitative determination of bile acids by gas chromatography

Article abstract of DOI:10.1016/0039-128X(82)90134-9

In order to find an artificial internal standard compound for quantitative determination of bile acids by gas chromatography, 7α,12α-, 7α,12β-, 7β,12α- and 7β,12β-dihydroxy-5β-cholan-24-oic acids were chemically synthesized with cholic acid as the first starting material. The gas chromatographic retention time of 7β,12β-dihydroxy-5β-cholan-24-oic acid (ββ-isomer) was more different from that of natural bile acids than the other isomers. Moverover, ββ-isomer was extracted in the same fraction as the bile acids from urine, and no urinary substance had the same retention time as ββ-isomer. No artifact was produced from ββ-isomer during the analysis procedure. It was concluded that the ββ-isomer is an internal standard compound with certain advantages for the quantitative determination of bile acids in urine by gas chromatography, irrespective of the recovery rate during the analysis procedure.