Tris(2,2'-bipyridyl)ruthenium(II) electrochemiluminescence sensor based on carbon nanotube/organically modified silicate films

摘要

In this paper, a novel electrochemiluminescence (ECL) sensor was constructed to determine herring sperm (HS) double-stranded (ds) DNA. Tetramethoxysilane and dimethyldimethoxysilane were selected as co-precursors to form an organically modified silicate (ORMOSIL) film for the immobilization of multiwall carbon nanotubes (MWNTs) wrapped by poly(p-styrenesulfonate) (PSS), and then Tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)_3~(2+)) was successfully immobilized on a glassy carbon electrode via ion-association. PSS was employed to increase the conductivity of the ORMOSIL film and disperse the cut MWNTs, which were cut and shortened in a mixture of concentrated sulfuric and nitric acids, in the film. It was found that MWNTs could adsorb Ru(bpy)_3~(2+) and acted as conducting pathways to connect Ru(bpy)_3~(2+) sites to the electrode. MWNTs also played a key role as materials for the mechanical and thermal properties. The ECL performance of this modified electrode was evaluated in a flow injection analysis (FIA) system, and the detection limit (S/N=3) for HS ds-DNA was 2.0 X 10~(-7) gmL~(-1) with a linear range from 1.34 X 10~(-6) to 6.67 X 10~(_4)gmL~(-1) (R~2 = 0.9876). In addition, the ECL sensor presented excellent characteristics in terms of stability, reproducibility and application life.