Chemiluminescence determination of sulphite using a cyclometalated iridium complex as chemiluminescence reagent

A simple, fast and accurate chemiluminescence (CL) method for the determination of sulphite has been developed, based on its sensitizing effect on the CL reaction between a novel water‐soluble iridium complex, [(dpci)₂Ir(bvbbi)](PF₆) (dpci = 3,4‐diphenylcinnoline; bvbbi = N,N′‐bivinylester‐¹H,^1′H‐[2,2′] bibenzimidazole) and cerium(IV). Under the optimal experimental conditions, the increased CL response was linear, with the concentration of sulphite over the range 5.0 × 10^–7–5.0 × 10^–4 mol/L. The detection limit of the method was 1.6 × 10^–7 mol/L, with a relative standard deviation (RSD) of 2.7% for nine repetitive determination of 1.0 × 10^–4 mol/L sulphite. The method was successfully applied to the quantitative analysis of sulphite in sugar samples. The possible reaction mechanism of sulphite on the [(dpci)₂Ir(bvbbi)](PF₆)–cerium(IV) system is also briefly discussed. Copyright © 2012 John Wiley & Sons, Ltd.