Electrochemical aptasensor based on Au@HS-rGO and thymine-Hg2+- thymine structure for sensitive detection of mercury ion

A sensitive electrochemical aptasensor was prepared on the basis of gold modified thiol reduced graphene (Au@HS-rGO) and thymine-Hg2+-thymine (T-Hg2+-T) constitution for the checkout of Hg2+. Firstly, Au@HS-rGO was fabricated as the substrate onto the glassy carbon electrode (GCE) surface, which facilitated the subsequent introduction of single-stranded DNA onto the electrode. Following that, thionine (Th) was immobilized on the electrode surface depend on the physical size effect of T and Hg2+. Finally, the amount of Hg2+ was determined by differential pulse voltammetry (DPV) of Th. Under the best conditions, the linear range of the aptasensor to Hg2+ was in the range of 1-200 nmol/L and the detection limit was as low as 0.38 nmol/L. Simultaneously, good selectivity and acceptable reproducibility were revealed in the designed aptasensor. Moreover, the design thought may provide an idea for the detection of other substances in the water sample.