Oxidation Reaction between Periodate and Polyhydroxyl Compounds and Its Application to Chemiluminescence

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Abstract
The oxidation reaction between periodate and polyhydroxyl compounds was studied. A strong chemiluminescent (CL) emission was observed when the reaction 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 our instrument. It was interesting to find that in the presence of carbonate the CL signal was enhanced significantly. When O2 gas and N2 gas were blown into the reagent solutions, both background and CL signals of the sample were enhanced by O2 and decreased by N2. The spectral distribution of the CL emission showed two main bands (λ = 436−446 and 471−478 nm). Based on the studies of the spectra of CL, fluorescence and UV−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 (1O2*) 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 1O2* and (CO2)2*. These two emitters contribute to the CL background. The addition of polyhydroxyl compounds or H2O2 caused enhancement of the CL signal. It may be due to the production of 1O2* during the oxidized decomposition of the analytes in periodate solution. This reaction system has been established as a flow injection analysis for H2O2, pyrogallol, and α-thioglycerol and their detection limits were 5 × 10-9, 5 × 10-9, and 1 × 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 α-thioglycerol was also prepared.