engleski

Detection of Cationic Surfactants in Disinfectants and Antiseptics by New Direct Potentiometric Surfactant Sensor

Cationic surfactants are used as disinfectants, bactericides, corrosion inhibitors and cleaning agents in home products and professional products in hospitals, industry, as oilfield chemicals and in agronomy. The positively charged head of cationic surfactants allows them to stick to negatively charged surfaces, preventing the electrostatic repulsion and also acting as textile softeners. Nonionic surfactants are amphipathic molecules that contain a lipophilic part, usually long alkyl chain or fatty acid, and a hydrophilic portion such as ethylene oxide chain of various length and thus, are nonionizable in water [1]. Nonionic surfactants enhance the cleaning properties of cationic surfactants [2]. Formulations of cationic with nonionic surfactants are common in many personal care products and pharmaceuticals [3, 4]. A newly synthesized cationic surfactant based on imidazole was used as counter ion to tetraphenylborate (TPB) to form the ionophore implemented in potentiometric surfactant sensor to detect cationic surfactants in commercial personal care products and antiseptics. The surfactant sensor showed good response characteristics to cationic surfactants usually used in commercial product formulations. with Nernstian slope from 57.1 to 59.1 mV/decade. The lowest limit of detection was obtained for cetylpyridinium cationic surfactant (1.1x10-6 M). Sensor exhibited fast dynamic response to dodecyl sulfate (DDS) and TPB, low interference influence and low pH influence. Ethoxylated nonionic surfactants had a significant influence on cationic surfactant detection with surfactant sensor in terms of end-point detection and shape and size of direct potentiometric titration curves. The sensor was successfully applied for the quantification of technical grade cationic surfactants and twelve products commercial personal care and antiseptic products with good agreement with referent two-phase titration method.

antiseptic, cationic surfactant, potentiometry, personal care products

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