Monitoring of trace element content in tap water from Karachuny Reservoir, Kryvyi Rih city

Control of the trace element content in tap water is particularly important for large industrial regions. The estimation of Cd, Pb, Cu, As, Ni, Zn, Mn, Hg, Se and Co concentration in the tap water of Kryvyi Rih city (Karachuny Reservoir) was accomplished using electrochemical methods, the most popular methods for determining the content of trace elements in natural objects and tap water. A simple and rapid method to determine trace elements in the tap water (Kryvyi Rih city) by inversion-voltammetry has been used. The concentration of trace elements was measured by voltammetricanalyzer AVA-2 device that implements the method of inversion voltammetry on a solid rotating electrode made of carbon material. The monitoring of the trace element content in the water of the Karachuny reservoir was carried out on a monthly basis between September 2018 and August 2019. The article presents the obtained voltamperograms of some trace elements, describes content of the trace element in tap water during the year (12 data for each trace element) and analyzes the compliance of drinking water in the city of Kryvyi Rih to the standards and normative indicators of drinking water quality.

Identification and Comparative Analysis of Alkaloids by Inversion Voltammetry Method

The alkaloids concurrent detection and identification in the samples by the method of multisensory inversion voltammetry is the purpose of the work. To achieve this goal, the proposed method has been substantiated, the composition of the electrochemical test system has been optimized taking into account the specifics of the detected substances, and informative signs that characterize the presence of alkaloids in the studied sample have been found. A new approach, consisting in the use of an electrochemical multisensor test system in the form of a solution containing a set of metal ions that can form complex compounds with organic substances, has been developed and scientifically approved. The results showed that each organic substance has a different effect on the electrochemical behavior of the multisensory test system. The use of such a test system made it possible to model the principle currently defined by the term "Electronic tongue". An electronic database has been prepared according to the results of the electroanalytical studies, which made it possible to identify the detected substance by comparing it with analyzed sample. The proposed electrochemical method, which is based on multisensor inversion voltammetry, allows the detection and identification of both narcotic drugs and psychotropic substances with high confidence for a small mass of the sample.

Features of the content of movable forms of heavy metals and selenium in soils of the Yaroslavl region

With the use of the method of inversion voltammetry there was analyzed the content of movable forms of trace elements: (selenium, zinc, copper, lead, cadmium) in soils in the Yaroslavl district of the Yaroslavl region, and also content of zinc, copper, lead, cadmium in soils and snow cover in the city of Yaroslavl. According to values of concentrations of movable compounds in soils determined trace elements can be ranked into the following row: zinc > lead > copper > selenium > cadmium. There was revealed insufficient if compared with literature data concentrations, content of movable compounds of selenium, copper and zinc in examined explored soils. The maximal concentrations of lead are revealed in the close proximity to both the city of Yaroslavl and large highways of the city. It indicates to the anthropogenic pollution of soils by this element.

Voltammetric Behavior, Identifying and Quantitatively Determining Iron-Based Nanoparticles, and Evaluating Their Stability in Simulated Solutions of Gastric Juice

The electrochemical behavior of Fe3O4 nanoparticles, iron nanoparticles coated with carbon, and diazonium salts by voltammetry methods using a carbon paste electrode (CPE) has been studied. There has been developed a voltammetric method for identifying and quantifying solid-phase iron-based nanoparticles in the background electrolyte of 0.02 mole/dm3 Trilon B (pH 3.5) with the use of the CPE. Investigations of nanoparticles’ stability with various coatings in a simulated solution of gastric juice have been carried out. Nanoparticles stability has been evaluated on the basis of determining Fe(III) ions in a simulated solution after contacting with nanoparticles within different periods of time using the method of inversion voltammetry. It has been shown that nanoparticles coated with carbon and salts of arendiazonium are the most resistant to aggressive media.

Concentration of arsenic in the tissues of cultivated mussel Mytilus galloprovincialis Lam., water and bottom sediments (Crimea, Black Sea)

Arsenic is one of the toxicants for which standards for maximum permissible concentrations in edible marine organisms have been developed. In view of this, monitoring of the content of arsenic in cultivated mussels, as well as in water and soil in the aquatic area of the marine farms for the cultivation of bivalve mollusks is important. The content of arsenic in the samples was determined using the method of inversion voltammetry. The average annual concentration of arsenic in the water area of the marine farm in the Karantinnaya Bay was found to be 1.2 times lower than those stipulated by the fishery standards, and in bottom sediments it was 1.5 times lower than those indicated in the “Dutch Lists” standards. The concentration of arsenic in the mussels is almost an order of magnitude lower than its maximum permissible concentrations in food and, in particular, in molluscs.