Colorimetric Detection of Cr3+ in Aqueous Solution Using AMT-modified Gold Nanoparticles

KeyWord:Cr3+ detection  3-amino-5-mercapto-1,2,4-triazole  gold nanoparticles  colorimetric sensor  water

Abstract:

      A colorimetric method was developed to determine chromium ions(Cr3+) in water,by using 13 nm diameter gold nanoparticles(AuNPs) synthesized by the citrate-mediated reduction of HAuCl4 as the transducer component for signaling color change,and 3-amino-5-mercapto-1,2,4-triazole(AMT) as the recognition element for Cr3+.AMT was assembled onto the surface of AuNPs to form a stable water-soluble AMT-AuNPs compound.In the presence of Cr3+,the specific binding of AMT and Cr3+ in solution could lead to the aggregation of AMT-AuNPs and a red shift of the maximum absorption wavelength,simultaneously producing an obvious color change from red to blue-purple,which could be used for Cr3+ visual detection.Under the optimized conditions(concentration of AMT:0.8 ¦Ìmol/L£»pH 7.0),the detection limit(3¦Ò) of the method could be as low as 100 nmol/L for Cr3+ with linear detection range of 6-14 ¦Ìmol/L,and there was almost no interference from other metal ions.With the advantages of fast response(5 min)£¬simplicity of preparation and manipulation,and no need of reading device,the presented method is promising in the application of on-site fast detection of Cr3+ in water.