SENSING OF POLY(STYRENESULFONATE)S BY POLYMERIC MEMBRANE ELECTRODES BASED ON LIQUID ANION-EXCHANGERS

The potentiometric responses of ion-selective electrodes (ISEs) based on various liquid anion-exchangers for poly(styrenesulfonate)s (PSSs) were examined. The liquid anion-exchangers included lipophilic monoamm onium, monophosphonium, diphosphonium, and triphosphonium salts. The m olecular weights of PSSs, which had narrow molecular-weight distributi ons (M-w/M-n < 1.2), were varied from 1.8 x 10(3) (PSS-1.8K) to 3.5 x 10(4) (PSS-35K). For PSS-1.8K, ISEs based on diphosphonium salts, poly methylenebis(trioctylphosphonium) dibromides 1-3, exhibited good respo nses, the response slope and linear response range being -20 to -21 mV /decade and 5.0 x 10(-5) - 5.0 10(-3) equiv dm(-3), respectively. As t he molecular weight of PSS was increased, the linear response range be came smaller, while the response slope was almost constant. Finally, P SS-35K gave almost no response. On the other hand, a wide molecular-we ight distribution PSS (M-w/M-n = 3.6) provided a good response, althou gh it had a high average molecular weight (M-w = 1.6 x 10(4)). Th, sel ectivity coefficients for PSS over various anions of ISEs, based on di phosphonium and monophosphonium salts, were assessed.