Theoretical and experimental approaches to the preparation, characterization and application of a newly synthesized mesoporous Zn-MOF as a selective ionophore for Ni(II) ion in carbon paste electrode matrix

Abstract

A novel carbon paste electrode (CPE) chemically modified with a newly synthesized Zn-metal organic framework (Zn-MOF) was synthesized for Ni(II) ion determination with impressing enhancement in sensitivity and selectivity over the preceding studies. Due to their electrocatalytic and substantial surface area criteria, MOFs are a reasonably new category of fascinating materials for precise electrochemical detection. Under the sonication condition, a novel Zn-MOF depending on a Schiff base ligand in nano size was synthesized, and it was characterized using different characterization methods such as powdered X-ray diffraction (PXRD), FT-IR, BET surface area, contact angle and scanning electron microscope (SEM) combined with energy dispersive X-ray analyzer (EDX). The BET surface area and contact angle measurement techniques results were 2901.08 m2 g−1 and 143.49°, respectively, for the synthesized MOF. It was concluded that under the ideal experimental circumstances, the produced Zn-MOF can extract and sense nickel ions from aqueous solution selectively. Several crucial factors were optimized to gain the ultimate electrochemical response. Response mechanism was proved by the aid of study of morphological change and functional groups chemical shifts. Ultimately, a calibration with a Nernstian slope of 28.75 mV decade−1 over linear concentration limits from 5.0 × 10−8 to 1.0 × 10−1 mol L−1 (R2 = 0.9990) and detection limit of 5.0 × 10−8 mol L−1 was obtained. The relative standard deviations and recovery ranges of the proposed approach for determining the Ni(II) ion in various water and food tests (n = 5) were 0.94–2.35% and 97.0–104%, respectively.