Electrochemical Sensing of Bisphenol A Using Metal Organic Framework/Quantum Dot Composite Modified Gold Electrode

Electrochemical sensors based on self-assembled monolayer (SAM) were synthesized using metal-organic frameworks (MOFs), quantum dots (QDs) and their composite (QDs@MOFs) to modify gold electrode (AuE) that was used as electrochemical sensors for bisphenol A detection. The molecular layer was assembled on the surface of the gold electrode by adsorption and provide a highly flexible method to tailor the interfaces between analyte and the electrode. Single crystal X-ray of the MOF revealed a six-coordinate copper(II) ion that bidentately coordinate two molecules of p-anisic acid and two molecules of 1H-benzimidazole to form a distorted octahedral geometry around the copper(II) ion. Electrochemical studies revealed that under optimal conditions, the modified gold electrode sensors show excellent sensing of bisphenol A, however, QDs@MOFs modified electrode is the best sensor with the highest oxidation peak current of 8.43E-05 μA and the lowest charge transfer resistance of 19.4 Ω within a wide concentration range of 0.1–1 μM and a limit of detection (LOD) of 0.252 μM. This could be attributed to the electrocatalytic activity of the composite (QDs@MOFs) modified sensor, and the synergistic effect of the MOFs and QDs in the composite. The LOD is comparable to other electrochemical methods of sensing BPA which indicates that QDs@MOFs modified gold electrode could be develop as sensor for BPA.