LUMINOL-SPECIFIC EXTRINSIC LYOLUMINESCENCE OF X-RAY-IRRADIATED SODIUM-CHLORIDE

Luminol produces chemiluminescence during the dissolution of F-colored alkali halides in aqueous solutions. There seems to be an unknown exc itation pathway which requires only the presence of luminol, hydrated electrons and alkaline conditions. This study was made using X-ray irr adiated sodium chloride as a primary radical-generating material, whic h allows the simultaneous generation of hydrated electrons and highly oxidizing chlorine-containing radicals by dissolution of the irradiate d solid in an aqueous solution. In alkaline solutions the reactions of chlorine-containing radicals with hydroxide ions can produce oxyradic als and hydrogen peroxide which suggest that chemiluminescence can be generated simultaneously by several pathways, and the emitting species can be either 3-aminophthalate in the case of chemiluminescence of lu minol, or the luminol molecule itself, or both. However, it was clear that the dissolution-uncovered holes were the primary species responsi ble for initiation of most of the luminescence observed. The present m ethod allows luminol detection below nanomolar level, and the linear l ogarithmic calibration range covers several orders of magnitude of con centration. Therefore, derivatives of luminol are proposed as labels i n lyoluminescence bioaffinity assays.