Metal-organic framework composite Mn/Fe-MOF@Pd with peroxidase-like activities for sensitive colorimetric detection of hydroquinone.

The construction of highly sensitive detection methods for hydroquinone (HQ) in environment and cosmetics is of great significance for environmental protection and human health. In this work, a novel detection method for HQ was successfully developed by constructing a metal-organic framework mimic enzyme colorimetric sensor (Mn/Fe-MOF@Pd 1.0) with excellent peroxidase-like activity, which was synthesized by doping manganese ions into Fe-MOF by introducing bimetallic active centers, thereby improving the peroxidase-like activity of Fe-MOF, and the acid resistance and stability of Mn/Fe-MOF were improved by supporting palladium (Pd NPs). It is proven that Mn/Fe-MOF@Pd 1.0 promoted the decomposition of hydrogen peroxide (H 2 O 2) to generate active species, therefore, oxidized chromogenic substrate discoloration. On this basis, the detection of HQ based on the Mn/Fe-MOF@Pd 1.0 colorimetric sensor was constructed, in which the limit of detection (LOD) was 0.09 μM in the linear range of 0.3–30 μM. Furthermore, Mn/Fe-MOF@Pd 1.0 was successfully used for detecting HQ in hydroquinone whitening cream and actual water samples. The successful synthesis of Mn/Fe-MOF@Pd 1.0 may provide new insights for further study of the enzyme-like activity of metal-organic framework composites, and the constructed facile and sensitive sensor system could broaden the application prospects of HQ detection. Schematic diagram of the synthesis of Mn/Fe-MOF@Pd and its colorimetric sensing of HQ [Display omitted] • A novel metal-organic framework composite Mn/Fe-MOF@Pd 1.0 was successfully synthesized. • The peroxide-like activity of Fe-MOF was increased by constructing bimetallic active sites. • The acid tolerance and stability of Mn/Fe-MOF were improved by loading palladium (Pd). • The mechanism of the peroxidase-like catalyzed reaction of Mn/Fe-MOF@Pd 1.0 was discussed. • The colorimetric sensor constructed by Mn/Fe-MOF@Pd 1.0 has high selectivity and sensitivity to hydroquinone (HQ). [ABSTRACT FROM AUTHOR]