Novel blue-emitting probes of polyethyleneimine-capped copper nanoclusters for fluorescence detection of quercetin

As an effective way to detect quercetin (Que), it was important to synthesize fluorescent probe with excellent performance by simple method. In this work, the facile one-pot approach was successfully developed to prepare blue-emitting copper nanoclusters (Cu NCs) by protection of polyethyleneimine (PEI) and chemical reduction in hydrazine hydrate. The water-soluble nanoclusters displayed the properties of strong fluorescence intensity and good stability. The PEI-Cu NCs showed maximum luminescence at 468 nm when excited at 375 nm. Based on the static quenching and inner filter effect mechanism, one sensitive and selective sensor for Que detection was established. The detection limit was 0.072 μM and two linear relationships existed in the range of 0.1–90 and 110–200 μM. Moreover, the PEI-Cu NCs probe was successfully employed to detect Que in real water samples. Graphic abstract In this work, rarely reported, polyethyleneimine-capped copper nanoclusters were applied in detecting quercetin with high sensitivity and excellent selectivity.