The Research On Preparation And Application Of A Near-Infrared Fluorescent Probe For Detecting Copper

With the continuous development of society, the problem of heavy metal pollution becomes worse and worse. As one of the essential trace element, copper is indispensable to organisms’ normal life activities. But high concentration of Cu2+ can cause gastrointestinal disorder, and even damage the liver and kidney. When the concentration exceeds a certain range in the body, it will cause serious copper metabolism disorders. Therefore, how to quickly detect the copper in sewage, drinking water, rivers, and organisms, and looking for effective method to detect copper are very important and urgent.The fluorescence detection method overcomes the disadvantages of the traditional methods, being simple, fast, selective specificity, high sensitive, low cost, and can be carried out in situ and visual detection. The near-infrared fluorescent probe with a longer excitation and emission wavelength can reduce background interference. So, designing and synthesizing a near-infrared fluorescent probe for detecting Cu2+are significant.By nucleophilic substitution reaction, we have characterized the structure of the two amino-substituted fluorescent probes:Cy-TPEN, Cy-15C5.This paper chooses heptamethine cyanine IR-780 as a fluorophore, pyridine derivatives and crown ethers 15-C-5 as recognition groups, respectively. We have applied the probe Cy-15C5 in the detection of Cu2+, the result shows that the fluorescence intensity of the probe decreased with the addition of Cu2+, and the color of the solution changes from blue-green to light pink obviously. Under optimal conditions, the linear relationship between the fluorescence intensity of the probe and content of Cu2+ conforms to the formula of Stern-Volmer equation, In addition, the probe Cy-15C5 detection range of 1.0×10-6～1×10-5 mol L-1. Moreover, Cy-15C5 featured high binding affinity with a low limit of detection of 8.3×10-7 mol L-1.In addition, we also applied the fluorescent probe to detect copper ion in water and food samples. At three spiked levels, the recovery of real water samples were 88.7% 110.8%. The contents obtained from fluorescent probe were consistent with those obtained via ICP-MS, indicating a higher accuracy of fluorescent probes to detect copper ions in food samples.This new near-infrared fluorescent probes provides an alternative for fluorescence detection technology of heavy metal ions.