Determination of bile acids in human faecal samples using supercritical fluid extraction and high-performance liquid chromatography

A supercritical fluid extraction (SFE) method for the extraction of bile ac ids from faeces is described. HPLC with pulsed amperometric detection was u sed to examine and confirm the recovery of bile acids. The analytes were ex tracted within a period of 75 min using supercritical carbon dioxide at a p ressure of 34.5 MPa and a temperature of 90 degrees C. In developing this m ethod the following parameters were investigated: temperature, pressure, an d extraction time. Two alternative methods of sample preparation were also investigated with a view to reducing the overall analysis time. The method was validated for the major primary and secondary bile acids found in faece s. It was found that the overall mean +/- SD recoveries were 102.1+/-7.92%, 111.6+/-9.91%, 112.1+/-9.92% and 113.7+/-9.92% for dry samples and 108.5+/ -15.77%, 110.0+/-7.22%, 115.9+/-11.11% and 106.6+/-9.16% for wet samples wi th respect to cholic, deoxycholic, chenodeoxycholic and lithocholic acid. T he SFE is an alternative to the traditional methods available. The extracti on is relatively easy to conduct and does not utilise as much glassware, so lvents or time. (C) 1999 Published by Elsevier Science B.V. All rights rese rved.