UTILIZATION OF LIPOPHILIC IONIC ADDITIVES IN LIQUID POLYMER FILM OPTODES FOR SELECTIVE ANION ACTIVITY MEASUREMENTS

Lipophilic anionic and cationic additives are investigated as componen ts for use in liquid polymer film-based optodes. These ionic additives are known to strongly influence the selectivity behavior of anion-sel ective electrodes, They also make it possible to construct ion coextra ction optodes that can measure anion activities. Theoretical, thermody namic anion-optode equilibria formalisms were derived to help understa nd the influence these additives have on the overall optode response a nd on the selectivity behavior. Neutral and charged anion carrier film configurations are described and tested for two anion ionophores with known modes of action, ruthenium(TI) octaethylporphyrin and a vitamin B-12 derivative (cyanoaquacobyrinic acid heptakis(2-phenylethyl ester )). These film configurations were further tested using a less well-un derstood ionophore, indium(III) octaethylporphyrin. Notable is the ind ium(III) octaethylporphyrin optode, which has a dynamic range appropri ate for physiological measurements of chloride at neutral pH values. A lso of interest is the optode with the vitamin B-12 derivative ionopho re, which has a dynamic range appropriate for some physiological measu rements of nitrite at neutral pH values.