A Highly Selective and Sensitive Fluorescent Probe Recognition for Co2+ in Aqueous Media Based on 8-Hydroxyquinolin-2-carbaldehyde-2-pyridylformylhydrazone Derivative

A new (8-hydroxyquinolin-2-yl)methylene picolinohydrazide derivative ( L ) has been successfully synthesized and characterized. The probe L displays high selectivity to Co 2+ in CH 3 CN/HEPES (1:1, Ｖ / Ｖ , 10 mmol·L −1 , pH=7.4) with a fluorescence "ON-OFF" response. The Co 2+ ion recognition event possesses some distinct features including rapid response, high selectivity and sensitivity, good anti-interference ability and being applicable within a wide pH range. Based on job's plot and ESI-MS studies, the 1:1 binding mode was proposed. The binding constant of L and Co 2+ is 1.63×10 8 L·mol −1 and the detection limit is 1.15 µmol·L −1 . Natural water samples experiments revealed that probe L can be potentially applied to the detection of Co 2+ in real environment.