TPB-DMTP@S-CDs/MnO2 Fluorescence Composite on a Dual-Emission-Capture Sensor Module for Fingerprint Recognition of Organophosphorus Pesticides

Residues of organophosphorus pesticides (OPs) raise considerable concern, while identifying OPs from unknown sources is still a challenge to onsite fluorescence techniques. Herein, a dual-emission-capture sensor module, based on a TPB-DMTP@S-CDs/MnO2 fluorescence composite, is developed for OP fingerprint recognition. TPB-DMTP@S-CDs/MnO2, synthesized by a hydrothermal method and self-assembly, is spectrographically validated as a dual-wavelength fluorescence source. OP-sensitive catalysis (acetylcholinesterase on acetylthiocholine chloride) is designed to regulate fluorescence by decomposing quenchable MnO2. A flexibly fabricated sensor module supports the optimal dual-wavelength fluorescence excitations and captures and converts fluorescence emissions into equivalent photocurrents for feasible access. The most prominent finding is that dual-fluorescence emissions alternatively respond to levels, species, and multi-pH pretreatments of OPs due to varied MnO2 sizes and distributions. Therefore, OP fingerprint recognition is conducted by refining the multidimensional information from fluorescence-triggered photocurrents and preset hydrolyzation using principal component analysis and the rule of maximum covariance. The recommended method provides a wide dynamic range (1 × 10-6 ∼ 12 μg mL-1), a good limit of detection (7.9 × 10-7 μg mL-1), 15-day stability, and good selectivity to guarantee fingerprint recognition. For laboratory and natural samples, this method credibly identifies a single kind of OPs from multiple species at trace levels (10-5 μg mL-1) and performs well in two-component and multicomponent analyses.