Electrogenerated chemiluminescence sensor based on a self-assembled monolayer of Ruthenium(II)-bis(2,2'-bipyridyl)(aminopropyl imidazole) on gold deposited screen printed electrode

A new electrogenerated chemiluminescence (ECL) sensor based on a self-assembled monolayer (SAM) of Ru(II)-bis(2,2'-bipyridyl)(aminopropyl imidazole) on a gold-deposited screen printed electrode (SPE) has been developed. Since the ECL emission of the Ru(II)-bis(2,2'-bipyridyl)(aminopropyl imidazole) complex can be easily obtained at an applied potential of less than +0.8V, the possibility of the oxidation of the Ru-complex SAM formed on gold-deposited SPE electrode surface was greatly diminished and thus the stability of the resulting Ru-complex SAM-based ECL sensor was enormously enhanced compared to the previously reported Ru(bpy)₃²⁺-derivative monolayer-based ECL sensors with applied potentials of more than +1.0V. In the present study, the gold deposited SPE with carbon nanotube paste was used in order to increase the amount of Ru-complex immobilized on the electrode surface through a large surface area of deposited gold nanoparticles causing good charge transport and thus leading to the increased sensitivity of the ECL sensor. The ECL characteristics obtained with the present Ru-complex SAM-based ECL sensor are compared with those obtained with other Ru(bpy)₃²⁺-SAM-based ECL sensors.