Sensitive and Selective Detection of Copper Ions Based on the Aggregation of Chitosan-Stablized Silver Nanoparticles

In this contribution, we present a simple and sensitive method for detecting Cu(2+)based on the Cu(2+)-induced aggregation of silver nanoparticle (AgNPs) capped with chitosan. Chitosan could be adsorbed on the surface of AgNPs, and keep AgNPs against aggregation. However, in the presence of Cu(2+), AgNPs aggregate again, the absorption decreases, and the color changes from yellow to colorless, which is due to the coordination of Cu(2+) and chitosan. The depressed intensity (Delta A) is in proportion to the concentration of Cu(2+) over the range of 3.33-40.0 mu M with the limit of detection (3 sigma) of 10.25 nM, the recovery of 92.60-104.20% and R.S.D. of 0.94-4.62%. The advantages of this method are simple, sensitive and low cost.