Coated Wire Cobalt (II) Selective Potentiometric Sensor Based on (2,4-Dinitrophenyl)-2-(Diphenylmethylene) Hydrazine

A precisely designed coated-wire cobalt ion-selective electrode (ISE) was created using a poly(vinyl chloride) matrix and 2,4-Dinitrophenyl)-2-(diphenylmethylene) Hydrazine as a neutral carrier. In the concentration range of 5.4×10−8 to 1×10−1 M, this new sensor demonstrated a good linear Nernstian response with a slope of 29.8 mV per decade change and an extraordinarily low detection limit of 3.4×10−8 M. The sensor demonstrated exceptional selectivity for Co (II) ions, outperforming mono-, bi-, and tri-valent other cations, while functioning efficiently in the pH range of 3.1–11.2. The selectivity coefficients (Kij) for the following ions were carefully calculated: Na+, K+, Li+, Ag+, Cr3+, Mn2+, Fe2+, Ni2+, Cu2+, Cd2+, Zn2+, Hg2+, Mg2+, Ca2+. The values of the coefficients ranged from 10−4 to 10−2. This sensor was effectively employed as an indicating electrode during potentiometric titration for cobalt ions alongside EDTA, demonstrating even more of its versatility. In addition, the ISE demonstrated its analytical capabilities by precisely identifying the amounts of cobalt in a range of environmental evaluations.