Use of spectral mapping and stepwise regression analysis for the assessment of the relationship between chemical structure and biological activity of surfactants

The biological activity of 27 nonionic surfactants with different hydrophobic moiety and with different length of ethylene oxide chain was determined on 10 microbiological objects. Spectral mapping technique and stepwise regression analysis were used for the separation of the strength and selectivity of the biological effect of surfactants, and for the elucidation of the relationship between molecular structure and activity. It was found that both the strength and selectivity of the biological effect of surfactants differ considerably from each other and considerably depend on the molecular structure. It was established that the strength of the effect mainly depends on the hydrophobicity of surfactants whereas both the hydrophobicity and the length of polar ethylene oxide chain exert a significant influence on the selectivity indicating the involvement of hydrophobic and hydrophilic forces in the surfactant-target interaction.