A highly sensitive tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)32+) electrogenerated chemiluminescence (ECL) sensor based on a graphene-titania-Nafion composite film has been prepared in a simple one-step manner. In the present work, a highly concentrated 0.1 M Ru(bpy)32+ solution was mixed with an as-prepared graphene-titania-Nafion composite solution (1:20, v/v), and then a small aliquot (2 µL) of the resulting mixture solution was cast on a glassy carbon electrode surface. This one-step process for the construction of an ECL sensor shortens the fabrication time and leads to reproducible ECL signals. Due to the synergistic effect of conductive graphene and mesoporous sol-gel derived titania-Nafion composite, the present ECL sensor leads to a highly sensitive detection of tripropylamine from 1.0 × 10-8 M to 2.0 × 10-3 M with a detection limit of 0.8 nM (S/N = 3), which is lower in comparison to that of the ECL sensor based on the corresponding ECL sensor based on the titania-Nafion composite containing carbon nanotube. The present ECL sensor also shows a good response for nicotinamide adenine dinucleotide hydrogen (NADH) from 1.0 × 10-6 M to 1.0 × 10-3 M with a detection limit of 0.4 µM (S/N = 3). Thus, the present ECL sensor can offer potential benefits in the development of dehydrogenase-based biosensors.
Keywords: ECL sensor; NADH; electrogenerated chemiluminescence; graphene; tris(2,2′-bipyridyl)ruthenium(II).