Ion-selective electrodes for the determination of salicylic acid: their operational features and application to analysis

摘要

It is shown that the super-Nernstian slope of the electrode function and minima in the potential-pH curves observed for salicylate-selective electrodes based on liquid ion exchangers can be explained to a first approximation by taking into account the extraction of salicylic acid in the molecular form into the membrane, in which it acts as a solvating additive with respect to ion associates and free salicylate ions. The selectivity of such electrodes for salicylate ions essentially depends on pH. A procedure is proposed for the rapid evaluation of the concentration of salicylic acid impurities in sulfosalicylic acid.