Colorimetric quantification and discrimination of phenolic pollutants based on peroxidase-like Fe3O4 nanoparticles

Given the great harm of toxic phenolic pollutants toward the environment and human health, exploring efficient and low-cost methods for their monitoring becomes strongly necessary. Herein, we propose a facile and high-performance sensor array for colorimetric quantification and discrimination of phenolic pollutants by employing Fe3O4 nanoparticles (Fe3O4 NPs) as a peroxidase mimic. The small-size Fe3O4 NPs exhibit favorable catalytic activity to promote the reaction of 4-aminoantipyrine, phenolic species and H2O2, giving a remarkable color change to indicate the level of the target. As a result, the approach provided linear response for phenol in the concentration range from 1.67 μM to 1.2 mM, offering a limit of detection down to 3.79 μM. By integrating the colorimetric array with principal component analysis, common phenolic compounds, including phenol, o-chlorophenol, m-chlorophenol, p-chlorophenol, m-aminophenol and o-nitrophenol, were well discriminated even at a very low concentration. These results suggest our sensor array as an effective tool to rapidly detect and differentiate phenolic contaminants in environmental and food matrices.