Copper ion-selective electrodes based on newly synthesized salen-type Schiff bases and their complexes

The paper describes research on ion-selective electrodes sensitive to copper(II) ions, in which Schiff bases and their Cu(II) complexes were used as active components of ion-selective membranes. The Schiff bases differ in the type and amount of substituents in the benzene ring and/or in the aliphatic chain. A multi-stage process of optimization of the ion-selective membrane composition was carried out. Apart from the selection of the best ionophore, the influence of the type of plasticizer and lipophilic salt as well as the active substance content was also investigated. The best results were obtained for N,N '-bis(5-bromo-2-hydroxy-3-methoxybenzylidene)2-hydroxypropylene-1,3-diamine and its dinuclear copper(II) complex. The ion-selective membrane composition was optimized, resulting in obtaining electrodes with a very good slope of 29.68 mV/decade in a wide measuring range 1 x 10(-6) - 1 x 10(-1) mol L-1 and good potential stability and selectivity. The electrodes could successfully work in the pH range of 2.4-5.5 for a minimum period of 2 months.

Automated summary

The paper discusses the research on ion-selective electrodes sensitive to copper(II) ions using Schiff bases and their Cu(II) complexes as active components of ion-selective membranes. Through the optimization of the membrane composition, electrodes with good performance were obtained.