Estimation of biological properties by means of chromatographic systems: evaluation of the factors that contribute to the variance of biological-chromatographic correlations.

The performance of chromatographic systems to emulate biological systems is evaluated in terms of the precision that can be achieved. The variance obtained when biological parameters are correlated against physicochemical ones can be decomposed in three terms: the variance of the biological data, the variance of the physicochemical data, and the variance caused by the dissimilarity between the two correlated systems (biological and physicochemical). The three terms contribute to the overall variance observed when measurements in chromatographic systems are correlated with experimental biological properties. The Abraham linear free energy relationships (LFERs) provide a very good approach to characterize biological and physicochemical systems and thus the variance of the analyzed data and the similarity/dissimilarity between them. The contribution of the three variances to the precision of the biological parameter estimated in this way is evaluated from the characterization of the biological and chromatographic systems by means of the Abraham model. The proposed method is able to estimate the goodness of chromatographic systems to predict particular biological properties. In particular, this method is illustrated by comparison of toxicity data (-log LC(50)) for the fish fathead minnow with retention data (log k) in several micellar electrokinetic chromatography (MEKC) systems and also by correlations between retention data (log k) in the sodium taurocholate (STC) MEKC system and data of several biological systems.