The new method, interrupted amperometry, is proposed to increase the sensitivity of amperometric measurements. Analytical possibilities of interrupted amperometry on solid electrodes are studied on an example of the determination of phenolic compounds in aqueous solutions.

Предложен новый способ повышения чувствительности амперометрических измерений – коммутационная амперометрия. Изучены аналитические возможности коммутационной амперометрии на твердых электродах на примере определения фенольных соединений в водных растворах.

A procedure was developed for sample preparation for the further determination of arsenic in potable and natural water and process solutions by stripping voltammetry (SV). To minimize the losses and simplify the procedure, arsenic(III) was oxidized by the ozonation or UV irradiation of the solution in the presence of sulfite, chloride, or hydroxide ions, which increased the oxidation efficiency. The time required for 100% oxidation does not exceed 60 s for an arsenic concentration of no more than 1 mg/L. The reduction to arsenic(III) was performed photochemically in the presence of sodium sulfite for 5 min. Further stripping voltammetric determination was performed in the same solution using a gold-plated carbon electrode. The developed procedure is rapid, simple, and easy-to-automate.

A rapid and sensitive technique for mercury determination by anodic stripping voltammetry is proposed. The carbon electrode modified with gold was used as an indicator electrode. The detection limit is 0.02 mu g/L for a 120 s deposition time. The influence of organic matter and inorganic interferences on the anodic stripping analysis of mercury was studied. The most popular methods of sample preparation were compared. Ozonation is the method of choice for rapid sample preparation of natural waters. For sample preparation of soil extracts the wet digestion with potassium peroxysulphate was selected. The procedure is applicable to the trace analysis of mercury(II) in different waters and soils.

A procedure was developed for determining mercury in natural water by stripping voltammetry on a gold-modified carbon electrode. The concentration dependence of the anodic stripping current of mercury is linear in the range 0.02–5 μg/L Hg(II). The interference of Fe(III), Cu(II), Cl–, Br–, I–, and F– ions with the determination of mercury was studied. Ozonation was used for rapid sample preparation. The detection limit for mercury was 0.02 μg/L at an electrolysis time of 5 min.