Thin-layer chromatography analysis of fructooligosaccharides in biological samples

This study presents the application of a rapid, simple and inexpensive thin-layer chromatography (TLC) for the analysis of fructooligosaccharides (FOSs) as feed additives (prebiotics) in complicated biological samples with minimal pre-treatment. Prebiotics have been monitored in different parts of the intestinal tract (jejunum, ileum and colon) of monogastric animals to which commercially available dietetic products containing fructooligosaccharides Raftifeed IPX, Raftilose and polysaccharide maltodextrin have been added into the feed. Thereby it contributes to a clarification of fructooligosaccharides and polysaccharides transformation in the digestive system. Chromatographic separation has been studied on different chromatographic systems (stationary and mobile phases). Optimal separation of fructooligosaccharides in dietetic products as well as in the samples from intestinal tract of monogastric animals has been achieved on glass-backed precoated silica gel layers impregnated with sodium acetate. The layers were developed with butanol–ethanol–water (5:3:2, v/v) in a vertical trough glass chamber with mobile phase vapour saturation. The visualisation of FOSs on chromatograms was performed with mixture of diphenylamine–aniline–phosphoric acid in acetone as primary detection reagent. Coloured spots of FOSs (blue–pink spots) on chromatograms have also been detected by reflectance densitometry at wavelength λ = 370 nm. Simultaneously, the concentration of acetic acid, which is one of FOSs fermentation product, was monitored in the intestinal contents from jejunum, ileum and colon by capillary isotachophoresis.