Electrochemiluminescence sensor using gold-nanoparticle modification combining mercaptoacetic acid-assembly

Abstract

In this paper, an electrochemiluminescence (ECL) sensor is fabricated using a covalent bond immobilization approach. A glassy carbon electrode (GCE) modified with gold nanoparticles (AuNPs@GCE) was prepared using a wet chemical method which acts as a support for the ECL reagent. A monolayer of mercaptoacetic acid (MA) was then assembled onto the AuNPs@GCE surface. Finally, an ECL reagent, bis(2,2 0 -bipyridyl) (5-amno-1,10-phen) dichlororuthenium [Ru(bpy) 2 (phen-NH 2 )] 2 2+ , was attached onto the AuNPs@GCE by condensation of the amino group and carboxylic group of MA. Because [Ru(bpy) 2 (phen-NH 2 )] 2 2+ is covalently immobilized on the electrode surface without any polymaterials and directly contacts to the electrolyte, in contrast to traditional ECL sensors fabricated using a polymer technique, mass transportation and electron transfer hindrance is negligible and ECL stability is increased obviously. The sensor is applied in cathodic ECL analysis and presents good performance in a linear range from 1.0 Â 10 À6 mol L À1 to 0.1 mol L À1 and a detection limit of 5 Â 10 À7 mol L À1 for potassium persulfate.