Graphene and AuNPs based electrochemical aptasensor for ultrasensitive detection of hydroxylated polychlorinated biphenyl

An electrochemical aptasensor for ultrasensitive detection of hydroxylated polychlorinated biphenyl (OH-PCB) was developed. In this work, the sulfydryl aptamer selected for OH-PCB was easily immobilized on the surface of the modified glassy carbon electrode via Au-S bond due to incorporation of gold nanoparticles/poly dimethyl diallyl ammonium chloride-graphene composite. The fabrication process of the electrochemical aptasensor was characterized by electrochemical impedance spectroscopy and cyclic voltammetry . The peak currents obtained by differential pulse voltammetry decreased with the increasing of OH-PCB concentrations. The current responded approximately logarithmically to the OH-PCB concentration ranging from 2.9 × 10 −11  M to 2.9 × 10 −7  M with excellent linear correlation performance. The detection limit of OH-PCB was estimated as low as 5.3 × 10 −12  M. The developed method had been successfully applied to analyzing lake water. Particularly, the method of the electrochemical aptasensor opens up a new perspective in environmental monitoring by the aptamer identification.