The behavior of polyaniline-coated PVC membrane based on 7,16-didecyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane for pH measurements in highly acidic media

Today the pH measurements are generally carried out by use of glass electrodes. These electrodes have become very popular due to their selectivity, reliability and dynamic pH range. Although, pH-sensitive [...]
Polyaniline (PANI) chemically coated on polyvinylchloride (PVC) membrane based on a neutral carrier 7,16-didecyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (Kryptofix 22 DD) as the active component has been developed for determination of pH values ranging from pH 0.1-1. Effect of experimental parameters such as membrane composition, nature and amount of plasticizer, lipophilic additives and thickness of PANI film on the potential response of the pH electrode was investigated. The electrode has an apparent Nernstian response slope of 54.5 [+ or -] 0.4 mV/pH (at 20[degrees]C). The equilibrium water content of the electrode was determined in pure water and NaCl solution (I = 0.1 mol/kg). The electrode had low electric resistance, good potential stability and reproducibility ([+ or -]1.5 mV, n = 10). It had a rapid potential response to changes of pH (15 s). The excellent performance in terms of linearity, stability and fast response makes this device suitable for pH measurements in highly acidic media. Keywords: polyaniline, 7,16-didecyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane, polyvinylchloride membrane, hydrogen ion-selective electrode DOI: 10.1134/S1061934814090020