A functional-based approach to the retention in thin layer chromatographic screening systems.

A QSRR approach, based on functional group counts, useful for prediction of the retention of any small organic solute with small molecule in seven TLC screening systems is presented. The equations are based on 154 possible substituents as the only molecular descriptors involved. The model optimization was performed by uninformative variable elimination-partial least squares (UVE-PLS), reducing the variables involved. The final equations, with 7-32 variables, explain 32-60% of overall explained variance and their predictive ability (Q(2)) includes in range 25-54% (LOO crossvalidation) and 12-43% (external validation). Their simplicity allows to computation without any complicated software.