Ratiometric fluorescence probe molecularly imprinted polymer encapsulating N, S, B doped carbon nanodots from waste Clematis Chinensis Osbeck for sensing furazolidone

Preparing carbon nanodots (CNDs) from waste traditional Chinese medicine (TCM) can take full advantage of the abundant chemical compositions in waste TCM, reduce the quantities required for disposal and the processing costs. In this study, N, S, B doped CNDs were synthesized by a hydrothermal method using waste Clematis Chinensis Osbeck, urea, thiourea, and boric acid as carbon, nitrogen, sulfur, and boron sources, respectively. N, S, B doped CNDs and red CNDs were encapsulated into molecular imprinted polymers (MIPs) to form a ratiometric fluorescence probe (CNDs@MIPs). By optimizing the preparation parameters (reaction temperature, reaction time and mass ratio), the relative quantum yield of N, S, B doped CNDs could be increased from 0.39% to 18.39%. The time-of-flight secondary ion mass spectrometry confirmed the elemental distribution of N, S and B and suggested the presence of active ingredients with anti-inflammatory and analgesic activities in the doped CNDs. The N, S, B doped CNDs could sense furazolidone (FZD) in a linear range of 5–700 mg/L with a detection limit (LOD) of 4.82 mg/L based on the mechanism of static quenching and the inner filter effect. The CNDs@MIPs probe could selectively sense FZD in the range of 5–400 mg/L with a LOD of 1.98 mg/L. In the different food samples, the recoveries of N, S, B doped CNDs and CNDs@MIPs were in the range of 90%–110%, indicating that the fluorescence sensors have excellent applicability for sensing FZD.