Colorimetric detection of Cu2+ based on the formation of peptide–copper complexes on silver nanoparticle surfaces

摘要

We developed a colorimetric method for the rapid detection of copper ions (Cu²⁺) in aqueous solution. The detection of Cu²⁺ is based on coordination reactions of Cu²⁺ with casein peptide-functionalized silver nanoparticles (AgNPs), leading to a distinct color change of the solution from yellow to red. The developed method has a good detection limit of about 0.16 µM Cu²⁺ using 0.05 mL of AgNPs stock solution and a linearity in the range of 0.08–1.44 µM Cu²⁺ with a correlation coefficient of R² = 0.973. The developed method is a useful tool for the detection of Cu²⁺ ions. Furthermore, it can be used for monitoring Cu²⁺ in water at concentrations below the safe limit for drinking water set by the World Health Organization.