Analytical Sciences

A Highly Sensitive Colorimetric Method for Copper Ions Detection Based on Controlling the Peroxidase-like Activity of Au@Pt Nanocatalysts

Yuan-Feng WANG,*,** Na PAN,*** and Chi-Fang PENG*,***

*State Key Laboratory of Dairy Biotechnology, Bright Dairy Co Ltd., No. 578, Wuzhong Road, Shanghai 200436, P. R. China
**College of Life and Environmental Sciences, Shanghai Normal University, No. 100, Guilin Road, Shanghai 200234, P. R. China
***State Key Lab of Food Science and Technology, School of Food Science and Technology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi 214122, P. R. China

In this study, a sensitive colorimetric method for the detection of copper ion (Cu²⁺) was developed based on controlling the peroxidase-like activity of (gold core)@(ultrathin platinum shell) nanocatalysts (Au@Pt-NCs). It was found that D-penicillamine can effectively inhibit the activity of Au@Pt-NCs. After being incubated with Cu²⁺, D-penicillamine lost inhibition toward the catalytic ability of Au@Pt-NCs. Based on the above interaction, a colorimetric detection of Cu²⁺ was develop by measuring the colorimetric signal variation of the H₂O₂-3,3′,5,5′-tetramethylbenzidine (TMB) reaction. This method exhibited high sensitivity and selectivity toward Cu²⁺ over a panel of other metal ions. The detection limit of this method was 3.7 nM and the linear range was 20 – 300 nM. Moreover, 20 nM Cu²⁺ can be distinguished directly by the naked eye. Furthermore, this method was applied to the analysis of water samples with good accuracy. These results demonstrated the excellent application potential of the method.

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