This article reflects the results of the study of analytical parameters for a series of Cd2+selective electrodes from various bibliographic sources, to highlight the nature of the ionophores and their application. A potentiometric sensor with polymeric membrane based on the selective complexation of the Schiff base N1,N5-bis(salicylidene-S-methyl)isothiocarbohydrazone and Cd2+ ion was assembled.FigureFigure 1. The structure of the ionophore N1,N5-bis(salicylidene-S-methyl)isothiocarbohydrazone.It has been demonstrated that the presence of the lipophilic additive sodium tetraphenylborate in the polymeric membrane significantly improved the slope. The electrode exhibits a Nerstian response within the range of 1.0·10-1 – 1.0·10-4 mol/L with the slopes mean 28.6 mV/decade, a response time of 20 seconds and the limit of detection of the sensor is 10-5 mol/L. The optimum pH range of the sensor is 2.0-8.5. Interference of some cations was also evaluated.The negative effect of the potentiometric measurements has Cu2+ and Pb2+ ions due to the possibility of their coordination with the polymer membrane ligand. To determine the cadmium content in the sample model the direct potentiometric method and as a potentiometric potential indicator in titration with standard solution of Trilon B are applied. The results indicate that this electrode is sensitive for determination of Cd2+. Potentiometric detection based on ion-selective electrodes offers advantages of speed and ease of procedures, simple instrumentation, relatively fast response time, wide dynamic range, reasonable selectivity, and low cost [1].