Potentiometric sensors based on organic ion exchangers for determining tetraalkylammonium salts

Abstract

Potentiometric sensors with plasticized polymer membranes based on organic ion exchangers, tetraalkylammonium dodecyl sulfates (benzyldimethyldodecylammonium, benzyldimethyltetradecylammonium, dimethyldistearylammonium), have been proposed for the determination of quaternary ammonium salts in model solutions and KATAPAV technical solutions. The thermal stability, composition, and solubility product have been estimated. It has been shown that ion associates are stable to 60–70°C, KS varies in the range from 2 × 10−8 to 5 × 10−10. The basic electrochemical parameters of the sensors have been determined as well, such as linearity ranges of the electrode function (5 × 10−5 (5 × 10−6)−1 × 10−2 (1 × 10−3) M) and slopes of the electrode functions (47–59 mV/pc), response time (60–90 sec), potential drift (2–3 mV/day), operation period (3–4 months), limits of detection for tetramethylammonium salts (1 × 10−5−4 × 10−7 M).