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.