UV-IRRADIATED POTASSIUM PEROXODIPHOSPHATE AND NITRATE AS EXCITATION SOURCES FOR LUMINOL CHEMILUMINESCENCE

Luminol-specific extrinsic lyoluminescence of UV-irradiated potassium peroxodiphosphate and potassium-nitrate has been studied. UV irradiati on of solid peroxodiphosphate can induce rupture of the peroxide bond and produce a stable solid solution of phosphate radicals in potassium peroxodiphosphate. The dissolution of the irradiated salt can liberat e phosphate radicals which initiate a luminol chemiluminescence-genera ting pathway in alkaline solution. UV irradiation of solid potassium n itrate induces partial photoisomerisation to potassium peroxonitrite, which has been previously reported to generate hydroxyl radicals durin g dissolution in aqueous solution. Support for hydroxyl radical genera tion was obtained and the hydroxyl radical was observed to be a key in termediate for strong chemiluminescence of luminol during dissolution of irradiated KNO3, in luminol sample solutions. Both lyoluminescence systems allow the detection of luminol down to sub-rud levels with lin ear calibration curves spanning five orders of magnitude of luminol co ncentration, suggesting that they can be used as tools in bioaffinity assays utilising luminol and isoluminol derivatives as labels.