6533b873fe1ef96bd12d4a98

RESEARCH PRODUCT

Gas chromatographic and mass spectrometric analysis of bile acids as trifluoroacetyl-hexafluoroisopropyl and heptafluorobutyryl derivatives

subject

description

Abstract The gas chromatographic retention times on QF-1 of 38 bile acids in the form of their trifluoroacetyl-hexafluoroisopropyl (TFA-HFIP), trifluoroacetyl-methyl, and heptafluorobutyryl derivatives are given. In general hexafluoroisopropyl ester trifluoroacetates proved superior with regard to simplicity of preparation, absence of artifacts, and resolution on QF-1. The main disadvantages of heptafluorobutyrates were the production of artifacts with some ketonic bile acids and the impossibility of separating any of the dihydroxy bile acids with substituents in the 3,6- and 3,7-positions. Mass spectra of TFA-HFIP derivatives were recorded with both direct and gas chromatographic inlet systems. The spectra of these derivatives are easily comparable with those of methyl ester trifluoroacetates and they enable the identification of positional isomers.