Visual detection of Cu(II) ions in water environment using gold nanoparticles modified with methanobactin

Abstract

A Mb-functionalized AuNPs system for copper ion detection based on coordination chemistry of Mb and copper ion to mediate the assembly of Mb-functionalized gold nanoparticles was presented. Mb-functionalized AuNPs solution was stable in red color. While the presence of Cu2+ induces significant assembly of Mb-functionalized AuNPs by forming Mb2-Cu coordination along with red-to wine red-to-purple-to-blue colour changes. The solution color was related to the assembly degree of Mb-functionalized AuNPs. Meanwhile, good linear relationship of Cu2+ along with A 645 nm/525 nm values could be obtained for its quantitative determination. Furthermore, Mb-functionalized AuNPs system shows excellent selectivity to Cu2+ against any other tested metal ions and anions, and good sensitivity with LOD of 3.26 nmol/L for real water samples.