Oligonucleotide Functionalized Microporous Gold Electrode for the Selective and Sensitive Determination of Mercury by Differential Pulse Adsorptive Stripping Voltammetry (DPAdSV)

Abstract

A novel electrode modified with oligonucleotide and microporous gold was fabricated for the determination of mercury by differential pulse adsorptive stripping voltammetry (DPAdSV). Microporous gold was synthesized by electrochemical reduction using dynamic hydrogen bubble template. The oligonucleotide was immobilized on microporous gold by self-assembly. The prepared electrode exhibited an improved electrochemical response for mercury(II) ion because of the large surface area and excellent electron transfer capacity provided by microporous gold and the specific coordination between mercury ion and thymine bases in oligonucleotides. Under the optimal experiment conditions, the oligonucleotide functionalized microporous gold electrode had a linear relationship between the stripping current and mercury ion concentration in the range from 0.5 to 30 µg/L with a detection limit of 0.021 µg/L. Moreover, the prepared electrode exhibited good selectivity, reproducibility, repeatability and stability. Furthermore, the prepared electrode was applied to detect mercury in tap water with satisfactory results.

Keywords:

• Mercury
• cyclic voltammetry
• differential pulse adsorptive stripping voltammetry
• scanning electron microscopy
• X-ray diffraction

Additional information

Funding

The authors gratefully acknowledge the financial support provided by the National Key Research and Development Program of China (2016YFD0401104, 2017YFD0400102), the National Natural Science Foundation of China (31671844, 31601543, 61301239), and the Natural Science Foundation of Jiangsu Province (BK20130505, BK20160506, BE2016306).