METHOD FOR DETERMINING ANTI-RADICAL ACTIVITY OF SUBSTANCES Russian patent published in 2021 - IPC G01N27/26 G01N27/00 

FIELD: chemistry.

SUBSTANCE: invention relates to the field of analytical chemistry, namely to the study of the properties of substances by means of voltammetric determination for estimation of the anti-radical activity of objects of artificial and natural origin with respect to OH-radicals. The method for determining the anti-radical activity of substances includes estimating the anti-radical activity by the degree of damage to the self-organising alkanethiol monolayer on the indicator electrode under the impact of generated OH radicals in presence and absence of the tested substances by means of voltammetric estimation of the analytical signal in a three-electrode electrochemical cell, wherein a mercury film electrode is used as an indicator electrode and a silver chloride electrode is used as a reference electrode, wherein, first, the voltammograms of the background current of oxygen electroreduction in a constant current mode in the potential range from 0 to -0.6 V are recorded, the indicator electrode is removed from the electrochemical cell and the working surface of the electrode is lowered ito a 1.0 M solution of alkanethiol in ethanol for 20 s, then the voltammograms of oxygen electroreduction are recorded using a thiolated indicator electrode, the electrode is removed and placed in a hydrogen peroxide solution at a concentration of 0.1 M and irradiated in the ultraviolet spectrum for 60 s followed by recording the voltammograms of oxygen electroreduction on the treated thiolated indicator electrode, the indicator electrode is removed from the electrochemical cell and the working surface of the electrode is lowered into a 1.0 M solution of alkanethiol in ethanol for 20 s, the electrode is returned to the electrochemical cell and the voltammograms of oxygen electroreduction are recorded, then the indicator thiolated electrode is removed from the electrochemical cell, placed in a hydrogen peroxide solution at a concentration of 0.1 M containing a solution of the analysed substance at a tested concentration, and irradiated for 60 s in the ultraviolet spectrum, then the thiolated indicator electrode is returned to the electrochemical cell, the voltammograms of oxygen electroreduction are recorded, and the coefficient of anti-radical activity R is determined by the formula: R=1-((Srs-St)/(Sr-St)), wherein S_t is the area under the voltammogram of oxygen electroreduction after the appliction of an alkanethiol monolayer; S_r is the area under the voltammogram of oxygen electroreduction after treating the thiolated electrode with free radicals in absence of the analysed substance; S_rs is the area under the voltammogram of oxygen electroreduction after treating the thiolated electrode with free radicals in presence of the analysed substance.

EFFECT: invention makes it possible to facilitated determination of anti-radical activity of substances.

1 cl, 2 dwg