The study of 2-methyl-8-hydroxyquinolines as ionophores for cation-selective electrodes

In this paper, a comparative study of cation-selective electrodes with the same polymer film composition was performed. The following components were used to prepare the membrane: polyvinyl chloride, a matrix in which all the components are embedded; tetrahydrofuran, a solvent for all components; ionophore 2-methyl-8-hydroxyquinoline; plasticizer 2-nitrophenyloctyl ether.3 sensors were assembled from the prepared membranes, and the sensors were preconditioned in Cu2+, Pb2+, Hg2+ solutions. The electrode preconditioned in solutions containing Hg2+ ions have an anionic function. The electrode preconditioned in solutions containing Pb2+ ions has a cationic function with a slope of 25 mV/decade of activity, a detection limit of 2.5·10-5 mol/L, and a concentration range, in which the Nernst function is respected 10-1-10-4M. The electrode preconditioned in solutions containing Cu2+ ions have a cationic function, with a slope of 25.9 mV/decade of concentration, a detection limit of 1.58·10-5 mol/L and a range of concentrations in which the Nernst function is respected 10-1 -10-4 mol/L.