New chemiluminescent method of acetylsalicylic acid determination based on terbium(III)-sensitized Fenton system

Oxidation of acetylsalicylic acid (ASA) and salicylic acid (SAL) is carried out with different oxidizing agents. In the study reported in this paper, ASA and SAL were oxidized with the use of a chemical source of reactive oxygen species (Fenton system) in the presence of terbium (III) or europium (III) ions. According to the kinetic and spectral analysis of chemiluminescence emitted in the systems Fe(II)/(III)-H2O2-ASA (or SAL)-Ln (III), the lanthanide (III) ions acted as sensitizers of the chemiluminescence studied. The highest intensity of chemiluminescence was observed in the system Fe(II)/(III)-H2O2-ASA-Tb(III) in which a linear dependence was obtained between the increase in the integrated emission intensity (Delta IINT) on the concentration of ASA varied in the range 3 x 10-7- 6 x 10-5 molL-1 (R = 0.9999), with LOD = 6.9 x 10-8 molL-1 and large tolerance to the presence of a number of foreign substances. A new, simple and fast method for ASA determination, based on the chemiluminescence of Fe(II)/(III)-H2O2-ASA-Tb(III) was successfully used for determination of this active ingredient in commercial pharmaceutical preparations.