▎ 摘　　要

An electrochemiluminescent (ECL) aptamer based method is described for the determination of thrombin. Three-dimensional nitrogen-doped graphene oxide (3D-NGO) was placed on a glassy carbon electrode (GCE) to provide an electrode surface that displays excellent electrical conductivity and acts as a strong emitter of ECL. The modified electrode was further coated with chitosan via electrodeposition. Finally, the amino-modified aptamer was immobilized on the modified GCE. The interaction between thrombin and aptamer results in a decrease in ECL. The assay has a linear response in the 1 fM to 1 nM thrombin concentration range and a 0.25 fM lower detection limit (at an S/N ratio of 3). The method was applied to the determination of thrombin in spiked human plasma samples, and recoveries ranged between 94 and 105% (with RSDs of <3.6%). The calibration plot was recorded at potential and wavelength of fluorescence emission (wavelength: 445 nm; potential: 0 to -2 V).