engleski

Potentiometric Surfactant Sensor Based on 1,3-dioctadecyl-1H-imidazol-3-ium tetraphenylborate

Surfactants are used in detergents in large quantities, thus they pose a significant environmental impact. A novel potentiometric sensor for anionic surfactants based on the new 1, 3-dioctadecyl-1H-imidazol-3-ium tetraphenylborate (DOI-TPB) ionophore is presented. DOI-TPB ionophore was characterized by computational and instrumental techniques (NMR, LC-MS, FTIR, elemental analysis). Computational analysis confirmed the feasibility of the DOI-TPB complex formation in solution and elucidated a range of C–H∙∙∙π interactions among flexible C-18 alkyl chains in DOI+ and phenyl groups in TPB– as dominant for their recognition in solution, (Figure 1), thereby providing guidelines for the future design of efficient potentiometric sensors. The calculated MM-PBSA binding affinity among components of ΔGBIND = –5.0 kcal mol–1 appears optimal, as it efficiently combines the ionophore stability with its ability to exchange anions in solution, thereby allowing favorable sensing responses. Experimentally the sensor showed a linear response to dodecylbenzenesulfonate and dodecyl sulfate in concentration ranges of 6.3 x 10-7 – 3.2 x 10-4 M and 5.9 x 10-7 – 4.1 x 10-3 M, for DBS and SDS, respectively. DOI-TPB sensor was successfully tested to quantify anionic surfactants in 12 commercially available detergents (powder, hand wash, and liquid gel detergents). The results showed good agreement with the standard method.

Anionic surfactants ; Computational analysis ; Detergents ; Potentiometric sensor

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