Application of selected topological indices to predict retention parameters of selected bile acids separated on modified TLC plates

The aim of this work was to apply some topological indices to predict chromatographic separations of selected bile acids such as: cholic (C), glycocholic (GC), glycodeoxycholic (GDC), chenodeoxycholic (CDC), deoxycholic (DC), lithocholic (LC) and glycolithocholic (GLC). The bile acids were separated on various glass and aluminum TLC plates precoated with silica gel only or with mixture of silica gel and Kieselguhr mixture impregnated with aqueous solution of 1%, 2.5% and 5% of CuSO4, MnSO4, FeSO4 and NiSO4. The mixture of n-hexane - ethyl acetate -acetic acid in various volume compositions was used as a mobile phase. Experimental R-F and R-M values obtained on all TLC plates modified with the use of inorganic salts were compared with respective topological indices of studied bile acids. It was suggested that of all indices only index C gives good correlation with chromatographic parameters R-F and R-M and can be useful for prediction of chromatographic separations of studied bile acids but only for their optimal separation conditions.