Hydrated electron-induced chemiluminescence of thallium(I) ion

Dissolution of X-ray irradiated sodium chloride or additively coloured pota ssium chloride induces generation of hydrated electrons which produce thall ium(I)-specific chemiluminescence in the presence of thallium(I) ions. Such a luminescence is also called extrinsic lyoluminescence (ELL) of X-ray irr adiation coloured sodium chloride, or additively coloured potassium chlorid e. The present ELL is considered chemiluminescence induced by dissolution-p roduced strong reducing and oxidising agents, i.e. hydrated electrons, surf ace-bound and only partially hydrated hole centres, and hydroxyl or sulphat e radicals (in the case of additively coloured potassium chloride dissolved in solution containing peroxodisulphate ions). Dichlorothallate(I) (Tl(I)C l-2(-)) was the main emitter in the ELL processes at about 430 nn. The redu ction-initiated excitation pathway of TlCl2- involves a colloidal thallium atom surrounded by chloride anions (Tl(O):2Cl(-)) while in the less importa nt oxidation-initiated excitation pathway the precursor of excited Tl(I)Cl- 2(-) is transiently existing T1(II)CI; produced by dissolution-uncovered ho le centres (or sulphate radicals). Both of the lyoluminescence procedures a llow Tl(I) to be detected below nanomolar concentrations, yielding linear l og-log calibration plots spanning several orders of magnitude of concentrat ion. (C) 1999 Elsevier Science B.V. All rights reserved.