An ordered one-step colorimetric sensor for the selective determination of catechol based on the polyacrylic acid-coated cerium oxide with laccase-like activity†

A one-step colorimetric sensing platform had been constructed for catechol determination based on polyacrylic acid-coated cerium oxide (PAA-CeO₂) with a significant laccase-like activity. Compared with the traditional nanozyme-based colorimetric determination methods for catechol, the PAA-CeO₂ nanozyme with laccase-like activity did not require biotoxic and poor stability H₂O₂ in this method. PAA-CeO₂ could directly catalyze the oxidation of catechol to o-quinone in the presence of dissolved O₂, and the oxidation product was coupled with 4-aminoantipyrine (4-AAP) to form a pink product at the maximum absorption of 512 nm (OD₅₁₂). By utilizing the relationship between the concentration of catechol and the OD₅₁₂ intensity to achieve sensitivity quantitative analysis and visual determination of catechol in an ordered and one-step reaction, which provided a dynamic range from 0.5 to 50 μmol L^?1 within a low detection limit of 0.121 μmol L^?1. In addition, this colorimetric sensing platform based on PAA-CeO₂ had satisfactory repeatability and stability, which could be used for the catalytic degradation of other phenolic compounds in the environment to ensure public health and environmental safety.