A Highly Selective and Sensitive Fluorescent Probe Recognition for Co^2＋ 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 CH3CN/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 Co2＋ is 1.63×10^8 L·mol^-1 and the detection limit is 1.15μmol·L^-1. Natural water samples experiments revealed that probe L can be potentially applied to the detection of Co^2＋ in real environment.