Study of the effect of ionophore carbon chain length on the selectivity of the Nd (III) ion selective electrode

Abstract

Ion selective electrode method is used for analyzing certain metal ions in a sample with ionophore as the link between two different solutions. The compounds 4-adipoybis (1-phenyl-3-methylpyrazolone-5) (H₂AdBP) and 4-sebacoylbis (1-phenyl-3-methylpirazolone-5) (H₂SbBP) are the same two types of ionophores but differ in the length of carbon chain. Both ionophores were used in potentiometric analysis of Nd³⁺ ion and showed that H₂AdBP-Nd electrode had a slightly smaller detection limit, namely 1.91 x 10⁻⁵M with a sensitivity of 15.9 ± 2.2 mV/decade with a response time of 23 seconds, compared to the H₂SbBP-Nd electrode with a detection limit of 2.88 x 10⁻⁵M, sensitivity of 21.9 ± 1.1 mV/decade and response time of 22 seconds. The effect of pH on the electrode performance was studied by varying the pH, concentration of ISA KNO₃ and composition of the internal solution. Good electrode performance was obtained at pH 3 and the electrode sensitivity increased to pH 4. The electrode selectivity was carried out using a separate solution method (SPM) for the La³⁺, Ce³⁺ and Th⁴⁺ ions. The determination results of \({K}_{Nd/j}^{pot}\) electrode pot showed that ESI-Nd electrode was not selective against La³⁺ and Ce³⁺ ions but selective to Th⁴⁺ with values \({K}_{Nd/j}^{pot}\) < 1.