Hybrid materials based on MF-4SK membranes and hydrated silica and zirconia with sulfonic acid-functionalized surface: transport properties and characteristics of DP-sensors in amino acid solutions with varying pH

Hybrid ion-exchange membranes of MF-4SK brand containing hydrated silica and zirconia nanoparticles with sulfonic acid-functionalized surface have been synthesized. The effect of modification on the properties of materials in the proton and potassium forms and the characteristics of potentiometric sensors based on these materials have been studied. It has been found that membrane modification leads to an increase in the ionic conductivity compared with that of the unmodified MF-4SK sample and, in some cases, to a decrease in diffusion permeability. Variations in the cation transport selectivity provided by the modification of MF-4SK membrane have made it possible to decrease the sensitivity of sensors to interfering hydronium cations in an acid medium and increase the sensitivity to amino acid anions and zwitterions in an alkaline medium. Optimum membrane compositions for the determination of histidine cations at pH < 7 and the simultaneous determination of potassium cations and methionine zwitterions and anions at pH > 7 have been selected.