Iron-doped poly(amidoamine)-based carbon dots with multienzyme-mimetic activities for dual-mode fluorescence and colorimetric detection of dichlorvos and Cr(VI)

Abstract

Dichlorvos and Cr(VI) are widespread environmental contaminants that pose significant risks to water quality, ecosystems, and human health. Therefore, the development of rapid, sensitive, and reliable detection methods for these pollutants is critically important. Although various techniques have been employed for the individual detection of these substances, achieving simultaneous and selective detection of both remains a considerable analytical challenge. In this study, iron-doped poly(amidoamine) carbon dots (PAMAM-Fe CDs) were synthesized, exhibiting multiple enzyme-mimetic activities, including peroxidase-, oxidase-, superoxide dismutase-, and catalase-like functions. Notably, dichlorvos and Cr(VI) were found to selectively influence the catalase-like and oxidase-like activities, respectively. Based on these findings, a dual-mode fluorescence and colorimetric sensing platform was developed, enabling rapid, sensitive, and selective detection of dichlorvos and Cr(VI), with detection limits of 1.69 × 10⁻⁵ µg/mL and 0.0418 µM, respectively. The applicability of this platform was validated through analysis of real-world samples, demonstrating satisfactory recovery rates and reproducibility. This work not only establishes a new approach for detecting dichlorvos and Cr(VI) for food safety and environmental monitoring but also provides new insights into designing multienzyme-active nanomaterials with significant practical potential.