Bimetallic metal-organic framework-based molecularly imprinted sensors for selective on-site detection of 2,4-dichlorophenoxyacetic acid

Designing and constructing simple and selective sensors for the on-site recognition of 2,4-dichlorophenoxyacetic acid (2,4-D) is both significant and challenging. Here, we report the development of molecularly imprinted sensors (Zn/Co-MOF@MIPs) utilizing bimetallic metal-organic frameworks as supporting carriers and catalysts, constructed via surface imprinting for the rapid detection and determination of 2,4-D. Zn/Co-MOF@MIPs exhibited oxidase-like activity, catalyzing the oxidation of 3,3 ',5,5 '-tetramethylbenzidine (TMB) to yield a blue-colored oxidized TMB in the absence of H2O2. The high affinity of the imprinted layer for 2,4-D selectively reduced the oxidase-like activity of Zn/Co-MOF@MIPs in the presence of 2,4-D, resulting in a significant decrease in blue color intensity. The absorbance at 650 nm gradually decreased with increasing 2,4-D concentration. Furthermore, we established a colorimetric method based on Zn/Co-MOF@MIPs for the rapid detection of 2,4-D in environmental water. This sensing platform exhibited sensitivity and selectivity for detecting 2,4-D, with a low detection limit of 2.26 mu M. These findings underscore the outstanding potential of Zn/Co-MOF@MIPs for environmental chemistry sensing applications.