A two-component polymeric optode membrane based on a multifunctional ionic liquid

Abstract

This work details the use of a 2-component optode membrane which is capable of generating three distinct colours in the presence of Cu 2+ and Co 2+ ions. It has been found that the ionic liquid (IL) trihexyltetradecylphosphonium dicyanamide [P 6,6,6,14 ][DCA] can act as plasticizer, ligand and transducer dye when used in poly(vinyl chloride) (PVC) membranes, which significantly simplifies the optode membrane cocktail. Upon exposure to an aqueous Cu 2+ solution, a yellow colour is generated within the membrane, while exposure to an aqueous Co 2+ solution generates a blue colour. Exposure to a solution containing both ions produces a green colour. Vibrational spectroscopy has been used to investigate the molecular basis of the IL-metal ion the binding mechanism. Analytical characteristics of the membranes including the effect of interfering ions, binding constants and the limit of detection for both ions have been estimated. Finally the case of simultaneous dual-analyte recognition is presented based on two distinct absorption maxima.

Applications of Ionic Liquids for the Development of Optical Chemical Sensors and Biosensors

“…70 IL can concurrently play three different roles, as a plasticizer, a ligand, and a dye transducer. 92 In gas analysis systems, the role of an IL depends on an affinity and a permeability of IL toward the gases and its ability to dissolve gaseous analytes. Additionally, we have found out some contradictions in interpretation of a role of IL in the process of fabricating CO2 sensing EC-based electrospun nanofibers.…”

“…Kavanagh et al 92 . The IL served concurrently as an ion-complexing ligand, a transducer dye, and a plasticizer.…”

“…The IL served concurrently as an ion-complexing ligand, a transducer dye, and a plasticizer. 92 Note that the content of IL in the sensing cocktail (66 wt%) 92 corresponded to the content of the traditional plasticizers for PVC such as dioctyl phthalate, dioctyl sebacate, and trioctyl phosphate. 114 As usual, the solvent for PVC was THF.…”

Wireless radio frequency detection of greatly simplified polymeric membranes based on a multifunctional ionic liquid

“…In our previous work we have detailed that the migration mechanism of metal ions from aqueous to organic phase is co-extraction of the metal and its counter ion into the membrane rather than the ion-exchange convention [30]. In this case as the metal ion transfers through the polymeric membrane boundary it complexes and neutralises the anionic ligand; the counter ion of the metal salt (NO 3 ) must therefore cross the membrane boundary in order to preserve electroneutrality within the membrane.…”

“…[P 6,6,6,14 ][DCA] acted as ion-exchanger, plasticizer, ligand and colorimetric dye in PVC based membranes, these membranes produced an optical response upon exposure to Cu 2+ (yellow), Co 2+ (blue) and both ions simultaneously (green) [30].…”