Supersensitive detection of auramine O in food and drug samples by using carbon dots as sensing reagents

This work present a highly sensitive fluorescence method for auramine O (AO) detection in food and drug samples based on carbon nanodots (CDs). The AO can effectively diminish the emission of CDs based on an integrated quenching mechanism of inner filter effect (IFE) and dynamic reaction. The CDs were prepared via a one-step hydrothermal method with citric acid and o-phenylenediamine as precursors. The good selectivity and high sensitivity feature of the proposed method for AO detection were validated. The fluorescence signals were linearly correlated with AO concentration over a range of 0.01‒10.0 µM with a detection limit of 36.3 nM was obtained. The proposed method was finally used for AO determination in traditional Chinese medicine, curry power, bean curb and candy samples with high accuracy. The recoveries ranged from 95.5 to 107.2% and relative standard deviations (RSDs) were less than 3.39%. This work provided a new insight and an operational access to AO detection in food and drug colorants monitoring. Thus, the CDs-based sensor demonstrated feasibility of rapid AO detection considering its appealing simplicity, rapidity and high sensitivity features.