MECHANISM AND ANALYTICAL APPLICABILITY OF LUMINOL SPECIFIC EXTRINSIC LYOLUMINESCENCE OF UV-IRRADIATED POTASSIUM PEROXODISULFATE

Luminol shows strong chemiluminescence with an emission maximum at sim ilar to 430 nm in the presence of sulfate radicals. Sulfate radicals w ere produced by the dissolution of UV-irradiated potassium peroxodisul fate powder in aqueous luminol solutions. The UV irradiation at 6.7 eV produces a solid solution of sulfate radical in potassium peroxodisul fate by rupturing -O-O- bonds, as in solution, but now the solid solut ion is stable in a time scale of years in dryness. In the present syst em, luminol chemiluminescence is produced via several parallel pathway s having a common triggering step, one-electron oxidation of luminol m onoanion by sulfate or hydroxyl radical. Present chemiluminescence all ows sensitive luminol detection from picomolar to micromolar level wit h a linear response over 5 orders of magnitude, after which luminescen ce is too strong for single-photon counting. The high sensitivity of l uminol detection allows us to propose extrinsic lyoluminescence of pot assium peroxodisulfate as a new and simple method for detection step o f bioaffinity assays using luminol or isoluminol derivatives as label compounds.