Influence of N$\text{}_{3}^{-}$ Ions on Chemiluminescence of the Eu(II)/Eu(III)-H$\text{}_{2}$O$\text{}_{2}$ System

The basic system of chemiluminescence investigations of relevant biological and inorganic compounds consists of Eu(II)/Eu(III) - H$\text{}_{2}$O$\text{}_{2}$. In these studies the increase in Eu(III) ion emission intensity usually results from an effective complexation reaction. In the present study, the N$\text{}_{3}^{-}$ ions are used as a ligand. The increase in the chemiluminescence intensity of the Eu(III) ion, the pH influence (in the range of 4.5-7.5) on the chemiluminescence intensity of the Eu(III) ion, as well as the quenching of the $\text{}^{5}$D$\text{}_{0}$ excited state of the Eu(III) ion are observed due to N$\text{}_{3}^{-}$ complexation. Taking into account the well-known Fenton system [Fe(II)/Fe(III) - H$\text{}_{2}$O$\text{}_{2}$], containing additionally the N$\text{}_{3}^{-}$, Eu(III) or Sm(III) ions, we found that the Eu(III) or Sm(III) ions were excited as a result of energy transfer process. A mechanism of the studied reactions is proposed.