Oxidation reaction between periodate and polyhydroxyl compounds and its application to chemiluminescence

The oxidation reaction between periodate and polyhydroxyl compounds was stu died. A strong chemiluminescent (CL) emission was observed when the reactio n took place in a strong alkaline solution without any special CL reagent. However, in acidic or neutral solution, it was hard to record the CL with o ur instrument. It was interesting to find that in the presence of carbonate the CL signal was enhanced significantly. When Oz gas and Nz gas were blow n into the reagent solutions, both background and CL signals of the sample were enhanced by Oz and decreased by Na. The spectral distribution of the C L emission showed two main bands (lambda = 436-446 and 471-478 mn), Based o n the studies of the spectra of CL, fluorescence and W-visible, a possible CL mechanism was proposed, In strongly alkaline solution, periodate reacts with the dissolved oxygen to produce superoxide radical ions. A microamount of singlet oxygen (O-1(2)*) could be produced from the superoxide radicals . A part of the superoxide radicals acts on carbonates and/or bicarbonates leading to the generation of carbonate radicals. Recombination of carbonate radicals may generate excited triplet dimers of two CO2 molecules ((CO2)(2 )*). Mixing of periodate with carbonate generated were very few O-1(2)* and (CO2)(2)*. These two emitters contribute to the CL background. The additio n of polyhydroxyl compounds or H2O2 caused enhancement of the CL signal, It may be due to the production of O-1(2)* during the oxidized decomposition of the analytes in periodate solution, This reaction system has been establ ished as a now injection analysis for H2O2, pyrogallol, and alpha-thioglyce rol and their detection limits were 5 x 10(-9), 5 x 10(-9), and 1 x 10(-8) M, respectively, Considering the effective reaction ions, IO4-, CO32-, and OH- could be immobilized on a strongly basic anion-exchange resin. A highly sensitive flow CL sensor for H2O2, pyrogallol, and a-thioglycerol was also prepared.