Gas chromatographic determination of the energy of interaction between some commercial pesticides and a non-ionic surfactant Original Research Article

Gas–liquid chromatography has been used for the determination of the energy of interaction between some commercial pesticides and the non-ionic surfactant tributylphenyl(ethyleneglycol)30. The energy of interaction was calculated from the temperature dependence of the retention time of pesticides. The similarities and dissimilarities between the retention behaviour of pesticides and gas chromatographic columns was evaluated by principal component analysis (PCA) followed by two-dimensional non-linear mapping and cluster analysis (CA). The energies of interaction of pesticides showed considerable differences. Significant linear correlation was found between the energies of interaction determined on Carbowax 20M and the surfactant column suggesting that their retention mechanism may be similar. This result makes probable that the pesticides bind to the polar ethyleneglycol moiety of the surfactant by hydrophilic (electrostatic) forces and the involvement of hydrophobic forces in the pesticide — surfactant interaction is negligible. The comparison of the results of PCA and CA indicate that both methods can be successfully used for the evaluation of the retention data matrix.