Europium-sensitized chemiluminescence of system tetracycline-H2O2-Fe(II)/(III) and its application to the determination of tetracycline.

Chemiluminescence (CL) of the reaction system tetracycline-H2O2-Fe(II)/(III)-Eu(III) was used for the determination of tetracycline hydrochloride in water, pharmaceutical preparations, and honey. The CL spectrum registered for this system shows emission bands typical of Eu(III) ions, with a maximum at lambda approximately 600 nm, corresponding to the electronic transitions of 5D0-->7F1 and 5D0-->7F2. A strong chemiluminescence intensity characteristic of europium(III) ions in the system tetracycline-H2O2-Fe(II)/(III)-Eu(III), as contrasted to the emission of the system tetracycline-H2O2-Fe(II)/(III) without Eu(III), proves that the Eu(III) ion plays the role of a chemiluminescence sensitizer, accompanying tetracycline oxidation in the Fenton system (H2O2-Fe(II)/(III)). A linear dependence was observed for the integrated CL light intensity on the tetracycline concentration in the range of 2x10(-7) to 3x10(-5) mol l(-1) with the detection limit of 5x10(-8) mol l(-1) in aqueous solution.