Electrochemical sensor capable of detecting trace mercury in water body, and preparation method and application thereof

Abstract

The invention discloses an electrochemical sensor capable of detecting trace mercury in a water body. The electrochemical sensor comprises a gold electrode, wherein gold nanoclusters are deposited on the surface of the reaction end of the gold electrode; and sulfhydryl-modified mercury-specific oligonucleotide probes are self-assembled on the gold nanoclusters. The preparation method for the electrochemical sensor comprises the following steps of: first, preparing the gold electrode; then, electrodepositing the gold nanoclusters on the surface of the reaction end of the gold electrode; and finally, self-assembling the sulfhydryl-modified mercury-specific oligonucleotide probes on the end surfaces of the gold nanoclusters so as to finish the manufacturing of the sensor. By using the sensor provided by the invention, the trace mercury in the water body can be detected; and the specific operation comprises the following steps of: first, placing the reaction end of the sensor in a water sample for reacting; then, immersing the reaction end into an anion double-stranded deoxyribonucleic acid (DNA) signal embedded agent for complete treatment; later on, connecting the sensor into an electrolytic cell of a three-electrode system and measuring the change of a response peak current by using square wave voltammetry; and finally, judging whether the water sample contains mercury ions on the basis of the change. The electrochemical sensor has the advantages of simple and practical structure, convenience in manufacturing, high sensitivity, high selection specificity and the like.

Description

technical field [0001] The invention relates to the technical field of detection of mercury ion content, in particular to an electrochemical sensor capable of detecting mercury ions, a preparation method and application thereof. Background technique [0002] Mercury and its compounds are very harmful to the environment and human health. The once famous "Minamata disease" was caused by mercury pollution in the environment. Mercury exists in various forms (inorganic, organic or mixed forms) in the environment, and enters the human body through long-term exposure or bioaccumulation through the food chain, which can harm the human brain, central nervous system, immune system, kidneys and other organs, causing multiple acute and chronic diseases. Therefore, efficient and sensitive monitoring and analysis of mercury content in food, water and the environment closely related to human life can not only meet people's requirements for a healthy living environment, but also understand...

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Problems solved by technology

[0003] Traditional mercury content analysis methods, such as coupled plasma mass spectrometry (ICP-MS), atomic emission spectrometry (AES), atomic fluorescence spectrometry (AFS), ion chromatography (IC), etc., most of these methods have huge equipment and relatively high operational requirements. High, high operating costs, and limited by the instrument itself and the detection environment, often require complicated pretreatment, which limits the popularization and application of traditional methods in the monitoring of trace mercury in environmental samples

In addition, there are several methods for mercury detection based on simple coordination chemistry or redox reactions of mercury ions, including such methods as optical detection and anodic electrochemistry utilizing organic fluorophores or chromophores, metal / semiconductor nanoparticles, or conjugated polymers. Detection of voltammetry, etc. These methods often have defects such as low detection sensitivity, poor detection specificity, or the need to add organic media during the detection process, and the analysis efficiency also needs to be improved

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