Tris(2,2′‐bipyridyl)ruthenium(II) Electrogenerated Chemiluminescence Sensor Based on Sol–Gel‐Derived V₂O₅/Nafion Composite Films

Mesoporous V 2 O 5 /Nafion composite films have been used for the immobilization of tris(2,2′‐bipyridyl)ruthenium (II) (Ru(bpy) ₃²⁺ ) on an electrode surface to yield a solid‐state electrogenerated chemiluminescence (ECL) sensor. The electrochemical and ECL behavior of Ru(bpy) ₃²⁺ ion‐exchanged into the composite films has been characterized as a function of the amount of Nafion incorporated into the V 2 O 5 /Nafion composite. The composite film with 80% Nafion content has the largest pore diameter (4.19 nm) and yields the maximum ECL response for tripropylamine (TPA) because of the fast diffusion of analyte into the film with large pores. Due to the enlarged pore size and enhanced conductivity of the V 2 O 5 /Nafion composite, the present ECL sensor based on the composite films exhibited around 2 orders of magnitude higher ECL response and one order of magnitude lower detection limit for TPA (10 nM) compared to those obtained with the ECL sensors based on other types of sol–gel ceramic/Nafion composite films such as SiO 2 /Nafion and TiO 2 /Nafion.