Fabrication and characterization of mullite nano-ceramic materials for use in carbon paste ion selective electrode to estimate carcinogenic Cd (II) ion in real and human samples

[Display omitted] •The so-gel approach has been employed to create nano mullite with an average particle size equal to 45.5 nm, and various techniques have been used to describe it.•Nano mullite has been utilized as an ionophore in a carbon paste electrode.•The suggested sensor has been employed for the Cd (II) ion determination in different real samples and exhibited Nernstian behavior (29.49 ± 0.24 mV decade-1).•The sensor under consideration exhibited a limit of detection of 1.0 × 10-8 mol/L.•The sensor under consideration had a 6-second response time. Ion-selective electrodes are preferable to competing electrochemical methods for potentiometric detections regarding operating convenience, speed, and cost. The development of a novel class of carbon-paste electrochemical sensor that exploits synthetic mullite (3Al2O3.2SiO2) nanoparticles as an ionophore is investigated in this research. These mullite nanoparticles were synthesized using the sol–gel process, and a variety of methods were utilized to characterize them, including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) coupled with EDAX, and Brunauer-Emmett-Teller (BET) analysis. Nano-mullite's crystal structure has been verified by the XRD technique and crystallite size was established by the Debye-Scherrer equation (average crystallite size 9 nm). SEM and TEM have verified its nanoscale (the particle size between 16.08 nm and 45.5 nm). The BET study confirms the huge surface area (82.1164 m2/g), average pore size equal to 5.323 nm, and mesoporous structure of the mullite nanoparticle. Mullite nanoparticles, which have a substantial surface area, a porous structure, nano size, and electrical activity, are incorporated into the electrode composition to speed up the processes of electron transfer. The modified carbon paste electrode (MCPE) has been estimated in the function of a selective sensor for cadmium ion detection. Under ideal conditions, the potentiometric approach verified a straight reactivity forward into Cd (II) ion in varying concentrations from 1.0 × 10-8 to 1.0 × 10-2 mol/L with a limit of detection of 1.0 × 10-8 mol/L and a Nernstian slope of 29.49 ± 0.24 mV decade-1. The paste composition that produced the best results had, in order, 67.3 % graphite, 3.5 % TCP, and 2.7 % nano-mullite. The designed sensor has a short response time of 6 s, may well be maintained for nearly 10 weeks in the pH interval of 3.0 to 8.0, and had good therma