Electrochemical aptamer sensor for highly sensitive detection of mercury ion with Au/Pt@carbon nanofiber-modified electrode

Abstract

In this paper, an electrochemical aptamer sensor was proposed for the highly sensitive detection of mercury ion (Hg2+). Carbon nanofiber (CNF) was prepared by electrospinning and high-temperature carbonization, which was used for the loading of platinum nanoparticles (PtNPs) by the hydrothermal method. The Pt@CNF nanocomposite was modified on the surface of carbon ionic liquid electrode (CILE) to obtain Pt@CNF/CILE, which was further decorated by gold nanoparticles (AuNPs) through electrodeposition to get Au/Pt@CNF/CILE. Self-assembling of the thiol-based aptamer was further realized by the formation of Au-S bond to get an electrochemical aptamer sensor (Aptamer/Au/Pt@CNF/CILE). Due to the specific binding of aptamer probe to Hg2+ with the formation of T-Hg2+-T structure, a highly sensitive quantitative detection of Hg2+ could be achieved by recording the changes of current signal after reacting with Hg2+ within the concentration range from 1.0 × 10−15 mol/L to 1.0 × 10−6 mol/L and the detection limit of 3.33 × 10−16 mol/L (3σ). Real water samples were successfully analyzed by this method.