Bile Compounds: Thin-layer (planar) Chromatography

With regard to the liquid chromatographic methods described for bile acid analysis, especially with regard to their determination in biological matrices, several approaches for qualitative and quantitative determination have been described. A critical evaluation of the advantages and disadvantages of these methods results in the conclusion that there are speciRc limitations for every application (Figure 3). Since cumbersome derivatization steps as well as laborious and unsuitable sample pretreatment play a key role in the value of the analytical results, technologies are needed where direct analysis of the bile acid pattern, especially in serum, is feasible. Only HPLC-MS coupling presently allows such analysis, but costly equipment and highly skilled personnel requirements limit this method to highly speciRc problems and makes it unsuitable for routine work. Presently, HPLC of bile acids is state-of-the-art and only incremental improvements can be expected from new column materials and microcolumns (H 1}2 mm). The future will be in the area of low cost, high throughput HPLC-MS devices for routine use.