Bile acids, such as cholic, chenodeoxycholic, deoxycholic, lithocholic and ursodeoxycholic acids, were allowed to react with hexafluoroisopropanol and trifiuoroacetic anhydride at 37" for 30 min. The resulting derivatives were gas chromatographed on QF-1, with flame ionization detection, and were identified by gas chromatography-mass spectrometry. Separation was good. By using this method, these acids were detected in samples of human duodenal fluid; the ratios of each were 24.4, 41.5, 24.9, 2.3 and 6.9x, respectively.
INTRODU-ON
:-K-IMA&Z.
-M&WR.$%. MASHSE, T+%U&i cakulatcd~ to-be 1.06, 1.80, 1.08, 0.10 and 0.30 mgfml, respectively, ~disregarding 1 losses (about iO%)~during-the extraction.
.~ ;
Discussion
As with acidic metabolites of cateeholamine5, C, CDC, DC, LC and UDC were easily derivatized with use of hexafiuoroisopropanol and trikoroacetic anhydride at the lower temperature. The results obtained by GC-MS show that the car-boxy1 groups of bile acids are selectively ester&d, and the hydroxyl groups acylated; with this reagent mixture.
The values estimated for bile acids in human bile by this method, i.e., 24.4, 41.5;24.9, 2.3 and 6.9 % for C, CDC, DC, LC and~UDC,~respectively, are consistent with those obtained by calorimetry after paper-chromatographic separationa. &cause it does not involve use of diazomethane, the method should be useful for the routine assay of bile acids in bioiogical fluids.