The Preparation Of Gold Nanoparticle Optical Probes And The Detection For Heavy Metal Mercury Ions

In recent years, heavy metal pollution is getting more and more serious, which has begun to affect people’s daily life. Therefore, the detection of heavy metals has gradually been referred to the agenda. However, traditional methods of detecting heavy metals such as the mass spectrometry or atomic absorption spectrometry are mostly rely on large and expensive instruments, they are cost-and labor-intensive, time-consuming and nonportable. Therefore, new、simple、low cost、high sensitive methods for heavy metal detection are highly desired. This paper reports a new method for Hg2+detection on the basis of previous.First, this paper briefly introduces the properties of gold nanoparticles, and then reports previous work for heavy metal detection on the basis of the gold nanoparticles. Then, this paper introduces the localized surface plasmon resonance of gold nanoparticles and its generating principle as well as excitation conditions.Next we prepared gold nanoparticles (AuNPs) using the sodium citrate reduction method. By changing the amount of sodium citrate and the reaction time, the parameters for preparing gold particles with a specific size were obtained. The gold nanoparticles prepared were then used as optical probe to interrelating detection.Then, we used the colorimetric response of gold nanoparticles promoted by ornithine to detect the mercury ions. Besides analyzing the principle of the detection method, we also explored the influence of the concentration of the gold sol and ornithine、the particle size of the gold particles on the detection of Hg2+. We got a naked detection limit for mercury ions with500nM, the detection limit can reach100nM with the help of UV-visible spectrophotometer. Finally, we examined its selectivity, the results show that our method for Hg2+detection has a good selectivity. Since the detection method can obtain the corresponding results directly through the eyes, the method is more practical, without relying on large equipment, fast response, low cost, and therefore can be applied to Hg2+detection.