Retention of neutral and basic heteroaromatic hydrocarbons in RPLC systems and its use in predictive studies. I. 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 Kow) and retention of apolar compounds in octadecyl-silica/methanol-water systems, first presented by Tomlinson and Hafkenscheid, is valid for neutral heteroaromatic hydrocarbons.

Prediction of environmental fate and effects of heteroatomic polycyclic aromatics by QSARs: the position of n-octanol/water partition coefficients.

The HPLC and TLC retention, n-octanol/water partition coefficients (log Kow), bioconcentration factors, and acute toxicity data of 29 heteroatomic polycyclic aromatic hydrocarbons and 7 parent polycyclic aromatics were determined experimentally. For the same set of compounds, molecular weights, fragmental log Kow values, and molecular connectivities were calculated. Quantitation of the mathematical relationships between the variables was used to validate the predictive potential of various parameters.

The role of the marabou stork (Leptoptilos crumeniferus (Lesson)) in Kenya in the spread of echinococcosis from the abattoir.

In experiments, adult marabou storks were fed with hydatid fluid of viable Echinococcus cysts obtained from sheep and goats. On microscopic examination of the birds' faeces no scolices were found, the only remaining undigested parts of the parasites fed being the chitinous hooks of the rostellum. The feeding trials have shown that the marabou does not play a role in the spread of echinococcosis from the abattoir.