Ultra-sensitive electrochemical sensors through self-assembled MOF composites for the simultaneous detection of multiple heavy metal ions in food samples

Using an assemble-able MOF material, we successfully constructed an ultra-sensitive electrochemical sensor based on Bi 2 CuO 4 @Al-MOF@UiO-67 nanocomposite material, in order to investigate the adsorption properties of the Bi 2 CuO 4 @Al-MOF@UiO-67 functional material on the heavy metal ion . The Cd 2+ , Cu 2+ , Pb 2+ and Hg 2+ can be detected at the same time. Selective recognition and enrichment of various metal ions on different substrates can be achieved through the assembly of a large number of Al-MOF and UiO-67-MOF nanomaterial composites with small particle sizes on the Bi 2 CuO 4 surface. Based on this, a new type of sensor is researched and prepared, which has been shown to have good stability and reproducibility. Due to its unique assembly structure, large active surface area , excellent adsorption capacity, and high electrical conductivity , Bi 2 CuO 4 @Al-MOF@UiO-67 presents outstanding performance. In addition, the sensor also exhibits excellent electrocatalytic redox capacity and high selectivity . The adsorption capacity of Cd 2+ , Cu 2+ , Pb 2+ and Hg 2+ is also significantly improved under the action of the sensor electrode, however, this is not the case. The limits of detection for Cd 2+ , Cu 2+ , Pb 2+ and Hg 2+ were found to be 0.02 pM, 0.032 pM, 0.018 pM and 0.041 pM, respectively. In order to investigate the detection mechanism of Cd 2+ , Cu 2+ , Pb 2+ and Hg 2+ was adsorption properties as well as electrochemical accumulation of Bi 2 CuO 4 @Al-MOF@UiO-67 on the metal atoms were investigated. This method has been successfully applied to samples of rice, sorghum, maize, milk, honey, and tea, and has enabled the simultaneous detection of Cd 2+ , Cu 2+ , Pb 2+ and Hg 2+ , which is of significant practical value.