Substrate Selectivity of an Electrochemiluminescence Pt Electrode Coated with a Ru(bpy)32+-Modified Chitosan/Silica Gel Membrane

The substrate selectivity of the known Ru(bpy)3 2+ electrochemiluminescence (ECL) is changed by coating a Pt working electrode with a Ru(bpy) 3 2+ -modified chitosan membrane and successively with a silica gel membrane that was prepared by the sol-gel method using tetramethoxysilane as a precursor. The double coating resulted in a high selectivity toward oxalic acid at pH 6.8, lowering relative ECL responses to trimethylamine, proline and 4-hydroxyproline about 2.8, 3.4 and 3.8 times, respectively, compared to those obtained with a Pt electrode coated singly with the modified chitosan.