TLC study of the binding of nonionic surfactants to the corn protein zein

The binding of 18 nonionic surfactants with various lengths of apolar ethylene oxide chains to the corn protein zein was studied by thin-layer chromatography (TLC) carried out on alumina layers covered with zein, and the effect of methanol, monovalent cations, and pH on the strength and selectivity of interaction was elucidated by using the spectral mapping technique and stepwise regression analysis. The binding of surfactants to zein has been demonstrated. It has been established that the number of hydrophilic ethylene oxide units in the surfactant molecule exerts the highest influence on the strength of interaction, and that the role of methanol and salt concentration is of secondary importance. The character of the cation and pH influenced both the strength and selectivity of the surfactant-zein interaction.