Solid-state electrochemiluminescence of two iridium(III) complexes

The electrogenerated chemiluminescence (ECL) of two water-insoluble iridium(III) complexes (pq)2Ir(acac)(pq = 2-phenyl quinolone anion, acac = acetyl acetonate) and (ppy)2Ir(acac)(ppy = 2-phenylpyridine anion) in carbon nanotube (CNT)/Nafion composite films was investigated at a glassy carbon (GC) electrode. CNT and Nafion play significant roles in the iridium(III) complexes immobilization. The excellent chemical stability and electrical conductivity of CNT promote electron transfer. The experimental conditions, such as potential, pH, concentrations of CNT and various coreactants were investigated. The iridium(III) complexes modified electrode had good stability and reproducibility. In our work, the (pq)2Ir(acac)/DBAE (2-(dibutylamino)ethanol) system was used to detect the codeine, one of the many narcotics, and the detection limit was 0.05 μM (S/N = 3). This method enabled the two water-insoluble iridium(III) complexes to be used for the determination of the analyte in aqueous solution.