Chromatographic and spectroscopic analysis of the fluorescent compounds derived from monosaccharides on HPTLC-NH2 Plates

In this paper we present results from recent studies focusing on elucidation of the mechanism of visualization of simple sugars (e.g. D-(+)-glucose, D-(+)-galactose, and D-(-)-fructose) developed on glass TLC plates precoated with 3-aminopropyl chemically bonded stationary phase and then heated at elevated temperatures, a method originally developed, then recommended commercially, by Merck. Detection of the sugars under UV illumination is possible because of their substantial fluorescence; this suggests that during heating the analytes probably undergo a process which results in their structural transformation. We postulated a possible analogy with the Maillard reaction, omnipresent in innumerable living organisms. To verify our assumption we performed analysis with high-performance thin-layer chromatography (HPTLC), high-performance liquid chromatography (HPLC), and IR, UV, and fluorescence spectroscopy. All the results obtained seem to confirm the analogy between the Maillard reaction and the reaction of simple carbohydrates after development on the amino stationary phase.