RETENTION OF NEUTRAL AND BASIC HETEROAROMATIC HYDROCARBONS IN RPLC SYSTEMS AND ITS USE IN PREDICTIVE STUDIES .1. CONCENTRATION OF THE ORGANIC MODIFIER

The retention of polynuclear heteroaromatic hydrocarbons in reversed-phase liquid chromatographic systems was studied using methanol-water or acetonitrile-water as the mobile phase. The relation between the concentration of the modifier and the capacity factor was investigated, and capacity factors in pure water were obtained by means of extrapolation of this relation and were used in quantitative chromatographic retention-activity relationships. It was shown that the general equation for the relationship between the n-octanol/water partition coefficient (log K(ow)) and retention of apolar compounds in octadecyl-silica/methanol-water systems, first presented by Tomlinson and Hafkenscheid, is valid for neutral heteroaromatic hydrocarbons. For basic heteroaromatic compounds, this relationship is not valid. Both log K(ow) and the logarithm of the bioconcentration factor in the guppy (Poecilia reticulata) of neutral heteroaromatic hydrocarbons can be predicted satisfactorily from capacity factors extrapolated to pure water.