The 1,3-Dioctadecyl-1H-imidazol-3-ium Based Potentiometric Surfactant Sensor for Detecting Cationic Surfactants in Commercial Products

Abstract

A low-cost and fast potentiometric surfactant sensor for cationic surfactants, based on the new ion-pair 1,3-dioctadecyl-1H-imidazol-3-ium-tetraphenylborate (DODI-TPB), is presented. The new cationic surfactant DODI-Br was synthesized and characterized by NMR, LC-MS, and elemental analysis, and was used for synthesis of the DODI-TPB ionophore. The DODI-TPB surfactant sensor was obtained by implementation of the ionophore in PVC. The sensor showed excellent response characteristics with near-Nernstian slopes to the cationic surfactants DMIC, CPC, CTAB, and Hyamine 1622. The highest voltage responses were obtained for DMIC and CPC (58.7 mV/decade of activity). DMIC had the lowest detection limit (0.9 × 10−6 M) and the broadest useful linear concentration range (1.8 × 10−6 to 1.0 × 10−4 M). An interference study showed remarkable stability. Potentiometric titration curves for the titration of cationic surfactants (DMIC, CPC, CTAB, and Hyamine 1622), with DDS and TPB used as titrants, showed sigmoidal curves with well-defined inflexion points and a broad signal change. The standard addition method was successfully applied with recovery rates from 98.9 to 101.2 at two concentrations. The amount of cationic surfactant found in disinfectants and antiseptics was in good agreement with the referent two-phase titration method and the surfactant sensor on the market. This new surfactant sensor represents a low-cost alternative to existing methods for cationic surfactant detection.

Study of Cationic Surfactants Raw Materials for COVID-19 Disinfecting Formulations by Potentiometric Surfactant Sensor

“…The DODI-TPB sensor for surfactants showed an excellent response to cationic surfactants with a nearly Nernstian response and a wide linear concentration range (up to 1.8 × 10 −6 to 1.0 × 10 −4 M) [ 37 ]. The titration curves of the pure cationic surfactants showed a sigmoidal shape, a high signal potential change, and well-defined inflexion points [ 37 ].…”

“…The DODI-TPB sensor for surfactants showed an excellent response to cationic surfactants with a nearly Nernstian response and a wide linear concentration range (up to 1.8 × 10 −6 to 1.0 × 10 −4 M) [ 37 ]. The titration curves of the pure cationic surfactants showed a sigmoidal shape, a high signal potential change, and well-defined inflexion points [ 37 ]. Therefore, the surfactant sensor DODI-TPB was tested on samples of technical grade cationic surfactants used as raw materials in the production of disinfectants and antiseptics.…”

“…Ionophore was prepared according to the procedure recently described [ 37 ]. A PVC-based liquid-type sensing membrane was prepared by mixing the high molecular weight PVC (Sigma-Aldrich, Hamburg, Germany); a selected hydrophobic plasticizer o -nitrophenyloctylether ( o -NPOE) (Sigma-Aldrich, Hamburg, Germany) with tetrahydrofuran (THF) (Merck, Darmstadt, Germany), all analytical grade; and a DODI-TPB ion-pair.…”

“…In our recent work, we presented and characterized a new 1,3-dioctadecyl-1 H -imidazol-3-ium tetraphenylborate ion-pair prepared from the new QAC 1,3-dioctadecyl-1 H -imidazol-3-ium cation [ 37 ]. This ion-pair was used to prepare a surfactant sensor based on a DODI-TPB [ 38 ] PVC liquid membrane.…”

Extending the Protection Ability and Life Cycle of Medical Masks through the Washing Process

“…During the global COVID-19 pandemic, cationic surfactants were extensively used as antiseptics and disinfectants [ 16 ]. Recent studies have shown that the growth in the production and use of surfactants was +196%, for biocides it was +152%, and for cationic quaternary ammonium surfactants (used as surfactants and biocides) it was +331% [ 17 ].…”