Construction of MGO@ZIF-8@MIPs as peroxidase-like nanozyme for the targeted colorimetric detection of perfluorooctanoic acid in water and milk

Abstract

Perfluorooctanoic acid (PFOA) poses a threat to the environment and human health due to its persistence, bioaccumulation, and reproductive toxicity. Developing and fabricating straightforward and selective sensors for the immediate identification of PFOA is substantial and demanding. In this paper, the advancement in the creation of molecularly imprinted sensors (MGO@ZIF-8@MIPs) utilizing magnetic graphene oxide (MGO) modified with metal-organic frameworks as substrates and catalytic agents is described. They were fabricated through surface imprinting technology for the quick identification and quantification of PFOA. MGO@ZIF-8@MIPs displayed peroxidase-like activity, facilitating the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to produce a blue-colored oxidized TMB in the presence of hydrogen peroxide (H₂O₂). The strong binding capacity of the imprinted layer for PFOA reduced the peroxidase-like activity of MGO@ZIF-8@MIPs in the presence of PFOA, leading to a notable reduction in the intensity of the blue color. The absorbance at 650 nm progressively declined as the PFOA concentration increased. On the basis of this, a colorimetric method based on MGO@ZIF-8@MIPs for the swift identification of PFOA in environmental water and milk samples was developed. This sensing platform demonstrated exceptional sensitivity and superior selectivity for the detection of PFOA, featuring a low detection limit of 0.12 μM. These results highlight the remarkable potential of MGO@ZIF-8@MIPs for applications in environmental and food sensing.