Colorimetric Detection of Copper Ions Based on Surface Modification of Silver/Platinum Cluster Nanozyme

A sensitive colorimetric method for detection of copper ions (Cu2+) was developed based on surface modification of Ag/Pt nanoclusters (Ag/Pt NCs) and regulation of the peroxidase-like activity. It was found that 3-mercaptopropionic acid (MPA) could inhibit the catalytic ability of Ag/Pt NCs, however it would lose the inhibition toward catalytic ability of Ag/Pt NCs after oxidization by oxygen through the catalysis of Cu2+. On the basis of this, a colorimetric method was developed for the detection of Cu2+ by measuring the colorimetric signal variation of the TMB-H2O2 reaction. This method exhibited high sensitivity and selectivity toward Cu2+ over a panel of other metal ions, in the linear range of 10-100 nM with a detection limit of 5.0 nM. The method was simple and low cost, and suitable for Cu2+ detection in real water samples.