Toxicological evaluation of harmful substances by in situ enzymatic and biological detection in high-performance thin-layer chromatography

The efficiency of a chromatographic analysis method is determined by the selectivity of the chromatographic separation and the specificity of the detection method. In the case of high-performance thin-layer chromatography (HPTLC) the separated components can be detected and quantified directly on the chromatogram by physical and chemical methods. By coupling high-performance thin-layer chromatography with biological or biochemical inhibition tests it was possible to detect toxicologically active substances in situ. A linear relationship was shown between the signal of the inhibition of cholinesterase and the concentration of the inhibitor using a constant enzyme concentration and a constant incubation time. The graph of the inhibition of the luminescence of Photobacterium vibrio fisheri in relation to the concentration of pentachlorophenol (range 20–80 ng) is nearly linear. Measurements were done by using a densitometer or a videodensitometric scanner.