Non-Enzymatic Electrochemical Sensing of Bisphenol A in Drinking Water and Milk Using Bimetallic Nickel-Copper Metal–Organic Framework

In recent years, there have been concerns about the toxicity of bisphenol A (BPA) in food packaging materials due to the potential endocrine disrupting effects it may have on humans, especially children and infants. In this present investigation, a free-standing nickel-copper pyridine-2,6-dicarboxylic acid (PDA) metal organic framework (MOF) anchored carbon nanofiber paper (Ni-Cu(PDA)MOF/CNF) was synthesized for the sensing and quantify the BPA analytes in milk and water. As-prepared bimetallic MOF hybrid materials are extremely porous, hydrophilic in nature with a huge surface area. This allows for the easy pathway of analyte molecules, which react with the redox-active metal sites of MOF matrix and enhance the sensitivity. During electrocatalysis reaction, various functional groups present in the MOF system can also act as dynamic adsorption sites. In the neutral medium (pH = 7.0), the Ni-Cu(PDA)MOF/CNF modified glassy carbon electrode (Ni-Cu(PDA)MOF/CNF/GCE) ascertained good catalytic activity and strong electrochemical sensitivity toward BPA with higher sensitivity value and lower limit of detection (LOD) value. The irreversible and diffusion-controlled oxidation reactions of BPA were observed. The bimetallic MOF modified electrode displayed an extensive linear ranging from 1 to 150 µmol/L with a LOD of 75 n mol/L for BPA detection. The MOF anchored electrode displayed exceptional anti-interference property, reproducibility and good storage stability up to one month. It is notable that the Ni-Cu(PDA)MOF/CNF/GCE has proved the competence of detecting BPA in milk and drinking water samples, which displayed satisfactory outcomes with chromatographic analysis.