Preparation Of Methoxy Polyethylene Glycol Stabilized Gold Nanoparticles And Their Applications For Detection And Absorption Of Acrylamide

In this paper, methoxy polyethylene glycol(PEG) stabilized gold nanoparticles( PEG-Au NPs) and thiol functionalized PEG stabilized gold nanoparticles(PEG-HS-Au NPs) have been prepared. Then these two gold nanoparticles were used in the detection and adsorptio n of the toxic small molecules, e.g. acrylamide, respectively.Firstly, the novel visual method for the detection of acrylamide by PEG-Au NPs has been developed. The PEG-Au NPs were characterized by transmission electron microscopy(TEM), ultraviolet spectrophotometer(UV), Dynamic Light Scattering(DLS). The results indicated that the size of the spherical Au NP core was 19 nm and well dispersed. In addition, the size of PEG-Au NPs(including Au cores and surface stabilizers) was around 40 nm. Significantly, 0.004 mg/m L acrylamide could induce the aggregation of the PEG-Au NPs, which caused the color changing of the colloidal solution from red to purple. The aggregations of Au NPs enhanced with the increase of acrylamide concentration from 0.004 mg/m L to 0.032 mg/m L. However, N, N-dimethylacrylamide could not induce aggregation of PEG-Au NPs under the same condition. Therefore, this method could provide new opportunities for the rapid, simple and selective detection of acrylamide.Secondly, PEG-HS-Au NPs were used to adsorb acrylamide. The adsorption capacity, adsorption mechanism and recycling have been studied. The PEG-HS-Au NPs were characterized by 1H-NMR, HPLC, TEM, UV and DLS, and the results indicated that the PEG-HS-Au NPs could adsorb acrylamide both in hydrophobic and aqueous media, but could not adsorb N, N-dimethylacrylamide. The adsorption was attributed to the hydrogen bonding between the proton in acrylamide and the oxygen atom in the PEG-HS-Au NPs. Each PEG-HS-Au NP could adsorb about 25772 acrylamide molecules in CH2Cl2, and about 22420 acrylamide molecules in aqueous media, which was less than that in CH2Cl2, This may due to the presence of the H2 O in the aqueous media which weakened the hydrogen bonding between the PEG-HS-Au NPs and the acrylamide. In addition, the PEG-HS-Au NPs could recycled 4 times with small agglomeration, and after 5 times, more than 50% gold nanoparticles are aggregated. This may due to the agglomeration during centrifugation process. Therefore, PEG-HS-Au NPs could be a new recyclable adsorbent for toxic sm all molecules.