Preparation of PVP-Cys CuNCs and Its Application in Determination of Berberine

Polyvinylpyrrolidone (PVP) and cysteine (Cys) double-ligand–modified copper nanoclusters (PVP-Cys CuNCs) were synthesized by a one-pot method. The addition of Cys can protect copper nanoclusters (CuNCs) more effectively and enhance its fluorescence intensity, compared with the single-ligand-modified PVP CuNCs; the double-ligand-modified PVP-Cys CuNCs showed higher fluorescence intensity and sensing ability. Based on the internal filtration and dynamic quenching effect of berberine (BBR) on PVP-Cys CuNCs, a novel, simple, and sensitive method for BBR detection has been established. This method exhibits a good linear response to BBR within the linear range of 1.09 × 10 −7 –4.26 × 10 −6 mol · L −1 , and with a limit of detection (LOD) of 3.67 × 10 −8 mol · L −1 . It has been successfully applied to the determination of BBR in practical pharmaceutical samples.