Adsorption of Triclosan on Sensors Based on PAH/PAZO Thin-Films: The Effect of pH

Triclosan (TCS) is a broad-spectrum antimicrobial, preservative agent widely used in pharmaceuticals and personal care products, considered as a troubling contaminant from the environmental point of view because of its toxicity, bacterial resistance promotion, and estrogenic effects. Under this compliance, the pernicious presence of TCS in the environment is requiring the development of molecular dedicated sensors, which in turn leads to the need to find adequate molecular systems capable of giving rise to a transduction. In this work, in order to investigate the affinity of TCS to common polyelectrolytes in an aqueous environment the adsorption of TCS on thin layer-by-layer (LbL) films of poly(1-(4-(3-carboxy-4-hydroxyphenylazo) benzene sulfonamido) -1,2ethanediyl, sodium salt) (PAZO) and poly (allylamine hydrochloride) (PAH) polyelectrolytes at different values of pH of the solution and changing the outer layer, PAZO and PAH, was investigated. Results demonstrated that the PAH layer is the most indicated to better adsorb TCS molecules. These results are of great importance for the development of TCS sensors based on LbL films, since it indicates that the outer layers of LbL films should be positive electrically charged.