“…In general, emitters of chemiluminescence reaction systems with cerium(IV) ions can be classified into five groups Ce(III) [8], excited sulphur dioxide (SO 2 *), excited products of oxidation of determined substance [18,19], dimols of singlet oxygen [20,35] and fluorophores [6,9,14]. Cerium (III), which is formed by the reduction of cerium(IV), is a well-known fluorescent ion, with the maximum emission at λ~355 nm [41][42][43] and therefore, it is a possible CL emitter. Excited sulphur dioxide species (SO 2 *) emit weak light at 300-450 nm [44,45], therefore the compounds showing strong fluorescence, such as rhodamine B [28,46], quinine [29][30][31] or lanthanide ions [32] are introduced to many reaction systems containing Ce(IV) ions.…”