MOF-Derived Nanoceria/Graphitic Carbon Nitride as an Efficient Electrochemical Modifier for Guanine Sensor with Diffusional Response

Abstract

This work presents a novel approach for the electrochemical detection of guanine (GU) using a MOF-derived nanomaterial. CeBTC MOF-derived CeO₂ nanoparticles, prepared by calcination and mixed with graphitic carbon nitride (g-C₃N₄) were structurally and electrochemically characterized and further applied in sensing of GU. XRPD, FTIR, SEM, and XPS measurements were used to study the composition, structure, and morphology of the nanoceria/g-C₃N₄ electrode modifier. Electrochemical impedance spectroscopy measurements and cyclic voltammetric studies indicated an improved electrocatalytic output of nanoceria/g-C₃N₄ modified carbon paste electrode (MOFdCeO₂/g-C₃N₄/CPE). The optimal content of electrode modifier in CPE, experimental conditions, and analytical technique parameters were established to achieve sensitive quantification of GU. Kinetic parameters of the electrochemical reaction of GU were determined and a diffusional response at an electrochemical sensor was achieved. The linear working range of the developed square-wave voltammetric method (SWV) in Britton Robinson buffer solution pH 3.0 at MOFdCeO₂/g-C₃N₄/CPE was recorded from 0.5 μM to 100 μM of GU, with a detection limit of 0.12 μM. The proposed guanine sensor showed good storage stability, repeatability, and selectivity, and its real sample applicability was successfully tested by quantification of guanine in spiked urine samples, with excellent accuracy and precision.