Potentiometric Surfactant Sensor for Anionic Surfactants Based on 1,3-dioctadecyl-1<i>H</i>-imidazol-3-ium tetraphenylborate
Nikola Sakač,
Dubravka Madunić-Čačić,
Dean Marković,
Lucija Hok,
Robert Vianello,
Valerije Vrček,
Bojan Šarkanj,
Bojan Đurin,
Bartolomeo Della Ventura,
Raffaele Velotta,
Marija Jozanović
Affiliations
Nikola Sakač
Faculty of Geotechnical Engineering, University of Zagreb, 42000 Varaždin, Croatia
Dubravka Madunić-Čačić
Faculty of Geotechnical Engineering, University of Zagreb, 42000 Varaždin, Croatia
Dean Marković
Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
Lucija Hok
Laboratory for the Computational Design and Synthesis of Functional Materials, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, 10000 Zagreb, Croatia
Robert Vianello
Laboratory for the Computational Design and Synthesis of Functional Materials, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, 10000 Zagreb, Croatia
Valerije Vrček
Department of Organic Chemistry, Faculty of Pharmacy and Biochemistry, University of Zagreb, A. Kovačića 1, 10000 Zagreb, Croatia
Bojan Šarkanj
Department of Food Technology, University North, 48000 Koprivnica, Croatia
Bojan Đurin
Department of Civil Engineering, University North, 42000 Varaždin, Croatia
Bartolomeo Della Ventura
Department of Physics “E. Pancini”—Università Di Napoli Federico II, 80126 Napoli, Italy
Raffaele Velotta
Department of Physics “E. Pancini”—Università Di Napoli Federico II, 80126 Napoli, Italy
Marija Jozanović
Department of Chemistry, University of Osijek, 31000 Osijek, Croatia
As anionic surfactants are used as cleaning agents, they pose an environmental and health threat. A novel potentiometric sensor for anionic surfactants based on the 1,3-dioctadecyl-1H-imidazol-3-ium tetraphenylborate (DODI–TPB) ionophore is presented. The newly developed approach for DODI–TPB synthesis is faster and simpler than the currently used strategies and follows the green chemistry principles. The DODI–TPB ionophore was characterized by computational and instrumental techniques (NMR, LC–MS, FTIR, elemental analysis) and used to produce a PVC-based DODI–TPB sensor. The sensor showed linear response to dodecylbenzenesulfonate and dodecyl sulfate in concentration ranges of 6.3 × 10−7–3.2 × 10−4 M and 5.9 × 10−7–4.1 × 10−3 M, for DBS and SDS, respectively. The sensor exhibits a Nernstian slope (59.3 mV/decade and 58.3 mV/decade for DBS and SDS, respectively) and low detection limits (7.1 × 10−7 M and 6.8 × 10−7 M for DBS and SDS, respectively). The DODI–TPB sensor was successfully tested on real samples of commercial detergents and the results are in agreement with the referent methods. A computational analysis underlined the importance of long alkyl chains in DODI+ and their C–H∙∙∙π interactions with TPB− for the ionophore formation in solution, thereby providing guidelines for the future design of efficient potentiometric sensors.
