FIELD: chemistry.
SUBSTANCE: invention relates to analytical chemistry, namely to method for determining the content of hydrogen peroxide in aqueous solutions by cyclic voltammetry using a three-electrode cell, where a graphite electrode modified with colloidal silver particles is used as an indicator electrode. Present invention determines hydrogen peroxide concentrations at a value of 1⋅10-10 M, and formation limit of 0.7⋅10-10 M. In a three-electrode cell filled with a solution of the background electrolyte 10 ml of tap water with the addition of 1 ml of 1 M NaOH, add 20 mcl of the first additive of unknown concentration of hydrogen peroxide, after which the vibrational stirring of the solution is performed for 20 s, a branch of the cyclic volt-ampere curve is recorded at a scan rate of 40 mV/s and a potential of -1.0 to +2.0 V, after which the cathode maximum is recorded on the current-voltage curve in the potential range from +0.4 to 0.0 V; further 50 mcl of the second additive of the certified mixture of hydrogen peroxide concentration 1⋅10-10 M, vibration stirring of the solution is carried out for 20 seconds, after which an anode branch is recorded, to the atomic branch of the cyclic volt-ampere curve at a sweep speed of 40 mV/s and a potential of -1.0 and +2.0 V, then the cathodic voltage-current dependence is recorded to increase the cathode maximum by a factor of 2 with respect to the first additive in the potential range from +0.4 to 0.0 V.
EFFECT: invention allows to lower the limit and the lower limit for determining the content of hydrogen peroxide in aqueous solutions.
1 cl, 2 dwg, 2 ex
