Thin-layer chromatography, TLC, HPTLC
Radiation transfer equation
Multilayer model (10 layers)
Analytical Chemistry and Spectroscopy
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Quantitative evaluation of TLC by direct photometric scanning is a promising method, in view of the development of cheap microprocessors: soon instruments for digital scanning will be commercialy available. In this paper we describe a multilayer model which seems to be a good approximation for solving the radiation transfer equation in the case of layer models with a gradient in an inward direction. Changes of remitted and transmitted light, in cases where a band lies in different layers, are presented. Examples shown are: the absorbance profile of a chromatographed band in the direction of scanning is approximated to that of an isosceles triangle; the concentration of the band is uniform, e.g. 0.3 A. U.; the concentration of the band is changing from 0 to 2.0 A. U. These results will serve to set up the correct algorithms for digital scanning and simultaneous determination in TLC.
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