Potentiometric Determination of the Al(III) Ion in Polluted Water and Pharmaceutical Samples by a Novel Mesoporous Copper Metal–Organic Framework-Modified Carbon Paste Electrode

Abstract

Metal–organic frameworks (MOFs) are attractive materials to be used as ionophores because of the array of nurturing features for instance a significant surface area, a porous structure, and also electrocatalytic activity. Aluminum is an important metal regarding its many applications such as in industry, biology, medicine, and so forth, so its estimation in very low levels is a challenging mission. Herein, a carbon paste electrode has been developed based on a novel prepared Cu-MOF with a nano-Schiff base linker. The prepared ionophore was characterized using many analytical and spectroscopic methods. The X-ray diffraction data suggested that the newly synthesized Cu-MOF has a mesoporous structure. For Al(III) determination in different real water and pharmaceutical samples, the established electrode has been successfully used with high precision (RSD% = 0.82–1.98) and accuracy (recovery % = 98.0–101.2) and showed good agreement with the atomic absorption spectroscopy results. The sensor under study exhibited Nernstian behavior toward the Al(III) ion (19.89 ± 0.63 mV decade–1) wrapping a large linear range of 1.0 × 10–7 to 1.0 × 10–1 mol L–1 with a low detection limit of 3.31 × 10–8 mol L–1. The working pH was 2.3–6.5 and the response time was 6 s. The fabricated sensor was highly selective for Al(III) ions. The response mechanism and surface reaction have been studied via scanning electron microscopy combined with energy-dispersive X-ray analysis and Fourier-transform infrared analysis.