A fast-response turn-on quinoline-based fluorescent probe for selective and sensitive detection of zinc (II) and its application

[Display omitted] •A quinoline-based fluorescent probe for detecting Zn2+ was developed by a simple condensation reaction.•The probe could quickly (less than 3 s) detect Zn2+ with a low detection limit and large linear detection range.•The probe was successfully applied to determine Zn2+ in real water samples and on test strips. A readily available Schiff base quinoline derivative, quinoline-2-carboxaldehyde (pyridine-2-carbonyl)-hydrazine (QCPCH), has been synthesized via a one-step condensation reaction. It is used as a turn-on fluorescent probe for detecting Zn2+ with high selectivity, sensitivity, and rapid response time of less than 3 s. In addition, the probe QCPCH shows a low detection limit of 72 nM and a large linear detection range (0–180 μM). The mechanism of probe QCPCH for sensing Zn2+ is proposed to be based on the combined effects of chelation-induced enhanced fluorescence (CHEF) and inhibiting photoinduced electron transfer (PET); this is further demonstrated by the Job's plot analysis, Benesi-Hildebrand study, FT-IR spectrum, and 1H NMR titration. Furthermore, the QCPCH is successfully applied to determine Zn2+ in real water samples, and is made into test strips for fast, convenient, quantitative and qualitative detection of Zn2+.