Green photoluminescent carbon dots: sensitive and selective optical detection of aclonifen pesticide

Abstract

This research developed an innovative fluorescent sensor using green and aqua-soluble carbon dots (CDs) to detect the pesticide aclonifen (AFN) in agricultural samples. The sensor is based on the direct inner filter effect (d-IFE) mechanism, which confers high sensitivity and selectivity. Blue fluorescence “N-Flavonoid-CDs” were synthesized from green sources such as spinach and gelatin through a hydrothermal approach that exhibited emission at 430 nm when excited at 320 nm. The absorption spectra of AFN overlap with the fluorescence emission spectra of N-Flavonoid-CDs; therefore, a shield effect occurs by adding AFN to the N-Flavonoid-CDs, preventing excitation of the N-Flavonoid-CDs. This phenomenon causes fluorescence quenching, which increases with higher AFN concentrations. The characteristics of N-Flavonoid-CDs and the extent to which AFN diminished N-Flavonoid-CDs' fluorescence were fully explored. The proposed fluorescent sensor exhibits a highly sensitive detection capability for AFN, with an impressively low detection limit of 0.05 μM and a linear response range spanning from 0.07 μM to 6.67 μM. Interferences, with similar structures to AFN and some other interference ions, were investigated, and the results confirmed the high selectivity, excellent accuracy, and recovery in detecting spikes in the suggested fluorescent sensor. This suggests that such fluorescent sensors can be effectively applied in food analysis and environmental detection.