Colorimetric Detection of Cobalt or Nickel Ions Based on the Change of the Catalytic Performance of Leached Ag Nanoparticles

A simple and rapid colorimetric detection method for Co2+ or Ni2+ was developed through Ag-CoO or Ag-NiO composite to increase catalytic performance to p-nitrophenol, which was formed when sodium borohydride was added to degrade p-nitrophenol. The content of Co2+ or Ni2+ was positive correlation to the catalytic performance. At the same time, different catalytic performance corresponds to different degradation degree of p-nitrophenol (different absorbance). The present strategy is based on different catalytic performance of Ag-CoO or Ag-NiO composite with different content of Co or Ni ions. The lowest concentration for Co2+ and Ni2+ to be detected was 10 nM and the linear detection range was 10 nM to 1000 nM. Present method was successfully applied for practical water sample.