Analytical Sciences

Development of a Mercury Detection Kit Based on Melamine-functionalized Gold Nanoparticles

Guoyan LIU, Huipeng REN, Yuyu GUAN, Ronghua DAI, and Chunyan CHAI

School of Agriculture & Biology, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, P. R. China

A fast and simple mercury detection kit was developed based on melamine-functionalized gold nanoparticles (GNPs). The detection kit contained reagent 1 (GNPs), reagent 2 (melanine), a reaction cuvette with four separated cells, a colorimetric card and a plastic pipette. The GNPs were prepared by a citrate reduction of HAuCl₄. A proper amount of melamine was applied to functionalize the GNPs. The complex reaction took place in the present of Hg²⁺ in the test samples, leading to the combination of Hg²⁺ with the C=N group of melamine located on the surface of the GNPs. This reaction resulted in damage to the stability of colloid gold, and the aggregation of GNPs occurred. Different color changes (from claret-red to lilac, purple and plum) were displayed with different concentrations of Hg²⁺ in the test samples. It was very easy and convenient to determine the amount of mercury ion by the naked eye. The advantages of this methodology are listed as follows: a short detecting time (within 10 min), a high specificity (no significant interference was indicated upon adding a certain amount of Cu²⁺, Pb²⁺, Zn²⁺, Mg²⁺, Cd²⁺ and Fe²⁺), high sensitivity with a detection limit of 0.01 mg L⁻¹ , easy operation and practical on-site use.

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