A TAPT-BTTA@MnO2-based fluorescence-colorimetric-photothermal multimodal sensing platform for reliable determination of organophosphorus pesticides.

BACKGROUND

Reliable determination of organophosphorus pesticides (OPs) is essential for food safety monitoring. However, most reported sensing methods rely on a single analytical signal, highlighting the need for multimodal sensing platforms with improved analytical reliability.

RESULTS

In this work, MnO2 Nanosheets (NSs) were in situ assembled onto a fluorescent covalent organic framework (TAPT-BTTA) to construct a multifunctional TAPT-BTTA@MnO2 composite. Benefiting from the fluorescence properties of TAPT-BTTA and the oxidase-like activity and thiocholine-responsive (TCh) behavior of MnO2, a fluorescence-colorimetric-photothermal multimodal sensing platform was established for OP detection. Under optimized conditions, the platform enabled sensitive determination of methyl parathion (MP), chlorpyrifos, phoxim, and triazophos, with fluorescence-mode detection limits of 0.29, 0.77, 0.22, and 0.15 μg/L, respectively. In addition, satisfactory recoveries ranging from 80.9 % to 99.24 % were obtained in spiked Astragalus samples, demonstrating good analytical accuracy and applicability.

SIGNIFICANCE: By integrating fluorescence, colorimetric, and photothermal outputs into a single sensing system, the proposed platform enables cross-validation among independent signals, thereby enhancing analytical reliability and reducing false-positive or false-negative results. This work provides a promising strategy for multimodal OP sensing and shows considerable potential for applications in food safety monitoring and pesticide residue screening.