| The heavy metals are widely distributed in nature, and its existence is a double-edged sword for human. In many fields, heavy metal is made to benefit humans as an irreplaceable and important role. On the other hand, using inappropriately or excessively may lead to environmental pollution, especially for water resource. Therefore, it is necessary to strengthen the monitoring for heavy metal in water solutions. At present, research of precious metal nanoparticles based sensing system for heavy metal ions has become a hot research subject in nanobiological fields. This paper will focused on the sensor for heavy metal ions in water solutions based on the silver and gold nanoparticles that are stabilized with generation5Polyamidoamine dendrimer (G5.NH2) and y-Polyglutamic acid, respectively. The Surface Plasmon Resonance (SPR) peak is changed after the adding heavy metal ions, which leads a change of particle sizes because the chelate effect and the interaction between nanoparticles and heavy metal ions.(I) G5.NH2was employed as a stabilizer to prepare [(Ag0)100-G5.NH2] by the reduction reaction. Due to the higher oxidizability of mercury ions, the reaction between mercury ions and elementary substance silver made a change of the size of [(Ag0)100-G5.NH2], and a corresponding color change from yellow to pale. So we used this redox reaction to create a colorimetric sensing method for mercury ions.The results showed that the synthesized [(Ag0)100-G5.NH2] could be used sensing for mercury ions by naked eyes and also could be used as a quantitative determination from10-10000μg/mL with a limit of detection of0.7μg/mL. But beyond that,[(Ag0)100-G5.NH2] doesn’t have a remarkable performance in the interference with other ions that are common be found in the earth. Good sensitivity and perfect selectivity ensure [(Ag0)100-G5.NH2] sensing system in the application of the detection of mercury ions in water solutions.(2) Gold nanoparticles were got from the reduction reaction by NaBH4with the y-Polyglutamic acid as a stabilizer. Because-COOH and-NH2are rich in γ-Polyglutamic, the aggregation of y-PGA-Au NPs were leaded by the addition of chromium ions, which were chelated with-COOH and leaded a corresponding color change from wine red to grey and the UV-Vis absorption change. For this reason, we developed a new method for sensing chromium ions by the relationship between the absorption value of SPR peak and the concentration of chromium ions.This study indicated that the prepared y-PGA-Au NPs could be stored for a long time at room temperature because of the good stability. When the concentration of chromium ions were90ng/mL and above, the test result could be seen by naked eye. The results of TEM showed y-PGA-Au NPs have minor diameter, so the detection effect was sensitive.Above that, we can draw a conclusion that this method is a simple, rapid and convenient detection method for sensing for chromium ions, the good selectivity and sensitivity made it a wide application in the field. |
PDF Full Text Request