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

摘要

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)](PF_6) (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)](PF _6)-cerium(IV) system is also briefly discussed.