Dual-Buffer Optimization and Docking-Supported Electrochemical Fluoride Nano-Detection Using UiO66-NDC

Abstract

A zirconium-based metal–organic framework, UiO66-NDC, constructed using 2,6-naphthalenedicarboxylic acid as an organic linker, was synthesized for the selective electrochemical detection of fluoride in water. The UiO66-NDC modified carbon paste electrode exhibited a significant enhancement in current response toward fluoride relative to the unmodified electrode, reflecting improved sensitivity and selectivity. Molecular docking analysis revealed a spontaneous and thermodynamically favorable interaction between fluoride and the UiO66–NDC surface, with the most stable binding conformation exhibiting a binding energy of –3.0 kcal mol⁻¹ and an estimated inhibition constant (Ki) of 6.23 mM, supporting the affinity between UiO66–NDC and fluoride ions observed experimentally. The sensor demonstrated consistent performance across different aqueous matrices, including tap water and milk samples, and showed good repeatability and operational stability over multiple measurements. Optimal sensing conditions were achieved in both acidic and alkaline medium environments, and interference studies confirmed selective detection of fluoride over common competing anions. The limit of detection was found to be 0.33 and 0.11 µM in NaOH and Acidic medium respectively. Comprehensive structural, morphological, and compositional characterization confirmed the stability and integrity of the synthesized UiO66-NDC. Overall, the findings establish UiO66-NDC as an efficient, cost-effective sensing platform suitable for environmental monitoring of fluoride contamination.