Determination of Salicylate by Selective and Sensitive Polymer Membrane Electrode: with Internal Solution and Solid Contact

In this work we developed a new salicylate-selective membrane based on the trioctylmethyl ammonium chloride as the ion exchanger. The treatment of membrane investigated and compared in two different types. In one type membrane put on the PVC tube, electrode with internal solution (IS), and in another type membrane glued on a glassy carbon electrode, solid contact electrode (SC). Both sensors show a Nernstian response (56±1.0 and 57.7±1.0 mV decade-1, respectively) to salicylate ions over a very wide concentration ranges (3×10-6?1 M and 1×10-6?1 M, respectively). The detection limits of these sensors are 1×10-6 and 8×10-7 M, respectively. The electrodes possess satisfactory reproducibility, very short response time (~ 5 s) in the whole concentration ranges, and discriminating ability for salicylate ions with respect to the most common inorganic anions and special organic and biological anions. The selectivity coefficients, linear range and detection limit were better for membrane that glued on glassy carbon electrode. Two electrodes could be used in pH rang 5.0 to 12.0. The electrodes were successfully used for determination of salicylate in real samples.