Evaluation and optimal combination of TLC systems for qualitative identification I: sulfonamides

A mathematical criterion for the evaluation of chromatographic analysis procedures is given by the information content as derived from Shannon's equation. This information content yields a numerical value representative of the merits of each chromatographic separation and thus allows selection of the optimal systems. In most cases, however, one analysis is not sufficient to allow the qualitative identification of the sample. Therefore, several chromatographic systems are combined. Two approaches allow the desired combination; one either calculates the information content of several procedures as one mathematical value or classifies the systems according to mutual resemblance by numerical taxonomy techniques. From the resulting groups of dissimilar systems, one optimal system can be chosen per group according to the information content. The results obtained by these mathematical procedures are illustrated with a practical example: the selection and evaluation of systems for the TLC analysis of sulfonamides.