The Synthesis And Performance Studies Of Salicylhydrazone Schiff Base Fluorescence Sensor

Metal is closely related to humans, it not only exists in nature in elemental form, but also exists in human body in the form of ions. The content of metal ions in the body is too much or loss will cause the body function disorder.Fluorescent probe, which are the molecules that the chemical and physical properties are able to change, can react with specific ion or chemical molecules. This change can be converted into signals that can be measured, such as the change of the fluorescence intensity, and ultimately achieves the goal of detection of specific chemical molecules or ions. Fluorescent probe have many advantages, such as high sensitivity, good selectivity, quick and easy. Therefore, looking for new high selectivity of metal ion fluorescence probe has become a hot research topic in the field of metal ion analysis testing. This paper mainly includes the following aspects:1. The research simple outlined the fluorescence analysis method, the generation of fluorescence principle, expounded the structure, characteristics, identification mechanism of fluorescent sensors, and mainly introduced the development and application of Schiff base fluorescence sensors.2. A new Schiff base fluorescence sensor, 3-Allylsalicylaldehyde salicylhydrazone（L）, for Mg²⁺ was designed and synthesized, and analyzed by FTIR, UV-spectrophotometer and 1HNMR. The influence of the fluorescence was investigated with the selectivity of metal ions, solvent, moisture content, p H value and interference ions. The experimental results showed that the fluorescence sensor that respond Mg²⁺ with highly sensitive and selective in DMF-H₂O（4:1, v/v） solution. L and Mg²⁺ had been coordinated with the stoichiometry of 2:1, and the detection limit was low to 4.88×10^-8 mol/L. At the same time, an accurate and sensitive method was developed and successfully applied to the determination of trace Mg²⁺ in certified and real samples with satisfactory results.3. Another new Schiff base fluorescence sensor, 2-Pyridine formaldehyde salicylhydrazone（A）, was designed and synthesized, and analyzed by FTIR, and UV-spectrophotometer. The influence of the fluorescence was investigated with the selectivity of metal ions, solvent, moisture content, p H value and interference ions. The experimental results showed that the fluorescence sensor that respond Al³⁺ with highly sensitive and selective in DMF-H₂O（9:1, v/v） solution. A and Mg²⁺ had been coordinated with the stoichiometry of 2:1, and the detection limit was 2.29×10^-6 mol/L.