Relevant physicochemical factors in chromatographic separation of Alternaria alternata mycotoxins

The solute-solvent interactions of Alternaria alternata mycotoxins, alternariol (AOH) and alternariol monomethyl ether (AME) were studied using spectroscopic and chromatographic techniques with the aim to rationalize the separation methods. The Kamlet and Taft's solvatochromic comparison method was applied to analyze the UV-Visible spectra and to compare with normal and reversed-phase high-performance liquid chromatography (HPLC) data. It is found that the normal phase chromatographic behavior of these mycotoxins can be predicted from the spectroscopic studies. The main factor involved in the chromatographic process is the hydrogen bond acceptor ability of the solvent. Due to the multicollinearity detected for the solvent parameters for hydroorganic mixtures used in reversed-phase HPLC, the factors involved were determined by the ridge regression. The tests performed show that in these cases the ridge regression could be the option to obtain statistical meaningful results. The results of the regression indicated a dependence of the retention parameter on the polarity-polarizability and hydrogen bond donor capacity of the solvent mixtures. Thus, the solutes seem to be much less sensitive to the hydrogen bond acceptor ability of the eluent than for normal phase HPLC. (C) 1998 Elsevier Science B.V. All rights reserved.