Application of the Ferguson principle to the antimicrobial activity of quaternary ammonium salts

Abstract
The activity of three quaternary ammonium salts, dodecyltrimethylammonium chloride, dodecyldimethylethylammonium chloride and dodecylpyridinium chloride, against M. aureus, E. coli and C. albicans has been determined and correlated with the surface properties of these compounds. The Ferguson principle has been applied by using surface concentration to estimate thermodynamic activity. Results obtained for the three quaternary ammonium salts and a particular micro-organism species were found to be in good agreement with each other when microbiological and surface studies were conducted under identical conditions.