Sensor Based On Gold Nanoparticles For Etching Reaction And Carry Out Real Application In Food Detection

In recent years,the research of nanotechnology and nanoscience has developed rapidly.Gold nanoparticles have become a research hotspot in recent years due to their advantages of readily synthesis,easy modification,and good stability,which demonstrates great application potentials in biomedical science and analytical fields.Therefore,on the basis of previous studies,we used gold nanoparticles as probes to develop a series of sensors based on etching reaction and carry out real application in food detection.Using nanogold particles as probes and UV-Vis spectrum and dark-field microscopes as detection approaches,a copper ion(Cu2+)sensor was constructed.The principle based on that,under acid conditions and with prescence of CTAB,Cu2+ could catalyze the reaction that oxgen oxide gold nanoparticles,which resulted in the reduction of diameter and corresponding decrease of UV-Vis absorption and scattering intensity under darkfield microscopy.Both of methods have a lowest detection limit toward Cu2+ as low as 50 nmol/L.Finally,we applied this method to detect copper ions in sea food to investigate its application value.A highly sensitive colorimetric sensor for the determination of iodide ion(I-)was constructed based on the catalytic reaction that trivalent iron(Fe3+)oxidized gold nanoparticles.The iodine content in salt was determined exactly.This method not only showed higher detection sensitivity but also was rapid and convenient.The detection range was 0.5-50 ?mol/L.The method expands the application of gold nanoparticle colorimetric sensors in food inspection.Chloride odium could be transformed to nitrosyl chloride under concentrated nitric acid,which can etch gold nanoparticles that was loaded on poly(vinylidene fluoride)(PVDF)film and lead to the reduction of size and color dodge.Based on the principle,we developed a paper-based colorimetric sensor for determining sodium chloride(NaCl).The intensity of paper was obtained by taking photos with cell phone and measure by ImageJ softwas,which was used to determine NaCl content quantatively.The content of NaCl can be detected as low as 0.01%.In contrast to other methods,such method was fast,safe and could be used on-site,avoiding the restrictions of equipment and sites.Our method would demonstrate a wide application in future.