Bile Acids

Bile acid derivative: Methyl acetate.

 

Reagents:

1.      0.5N HCl in methanol.

2.     Pyridine

3.      Acetic anhydride.

 

Procedure:

1.  Incubate unlabeled bile acid standard and samples with 0.5ml of methanolic HCI at 70��C overnight.       

2. Dry the sample under nitrogen.

3. Add 100ml of pyridine and 100ml of acetic anhydride and heat at 100��C for 90 minutes.  Dry under nitrogen.

4. Add hexane as solvent for GC/MS analysis.

 

GC/MS

Instrument: HP6890 GC system connected to the HP5973 mass selective detector.

GC column: HPUltra1, length-12m, 250mM, programmed at a constant He flow of 1ml/min.

Inlet temp. 260^oC, split mode.

Oven temperature programmed as follows: 170^oC for 2 min, then a 35^oC/min ramp to 278^oC and hold for 6min.

 

Retention Times for Bile Acids

Bile Acid                                 Retention Times

Cholic Acid                             7.70 min

Lithocholic Acid                     6.38 min

Chenodoxycholic Acid                  7.24 min

Deoxycholic Acid                          6.97 min

 

Reference: Fukada, Y., Kimura, K., Ayaki, Y. Effect of Chitosan on Intestinal Bile Acid
Metabolism in Rats. Lipids. Vol. 26. pp 395-399.