Relevance. The need to accurately determine the concentration of methionine in various biogeochemical samples. This amino acid serves as a precursor for the biosynthesis of proteins and peptides, as well as a donor of methyl groups, making it an essential participant in numerous biochemical processes, including cysteine synthesis. Additionally, methionine can be found in certain proteins, such as casein. Methionine is a widely used pharmacological drug that has a lipotropic effect and a positive impact on liver function. It enhances the synthesis of phospholipids, choline, and lecithin, as well as having an antidepressant effect due to its s-adenosylmethionine content. It is also a radioprotector and can be used in cancer diagnosis. Methionine is commonly used as an amino acid supplement in poultry and cattle feed, as well as in sports nutrition and medicine. Aim. To investigate the dependence of the metrological characteristics of electrochemical sensors for methionine on the morphological properties of palladium nanoparticles and the composition of the low-molecular reducing agents used for their synthesis. Methods. Transmission electron microscopy, cyclic voltammetry. Results and conclusions. The paper considers the effect of the reducing agent nature on the morphological characteristics of palladium nanoparticles and the composition of their micelles. Sodium borohydride, sodium citrate, and a mixture of borohydride and sodium citrate were used as reducing agents. All the synthesized nanoparticles have a cubic face-centered crystal cell. The composition of the micelles depends on the reducing properties of the reagents used. The reasons for the improved metrological characteristics of methionine determination on an electrochemical sensor based on palladium nanoparticles obtained using sodium citrate are associated with the growth of a shell on the nanoparticle core material, forming a heterostructure.

The paper demonstrates that systematic control over agricultural products contributes to the sustainable development of this industry in the interests of food security and nutrition. A comprehensive approach has been implemented to the issue of assessing the quality of livestock slaughter products. The approach is based on various systems of specialized measures, as well as such important indicators associated with changes in skin diseases of various clinical, biochemical, anatomical, morphological and visual etiologies. These evaluation criteria are necessary to obtain an opinion on the quality of livestock products. Thus, they must be taken into account when conducting veterinary and sanitary examination in laboratories. To assess the state of health and predict changes in the quality of slaughter products, great importance belongs to the study of patterns in clinical, anamnestic, morphological, metric and anatomical indicators of the animal body. The use of their patterns and these characteristics of changes made it possible to identify certain chains of patterns that formed the basis of innovative rules in the veterinary and sanitary assessment of sheep slaughter products. These innovations make it possible to anticipate the occurrence of dermatitis of various etiologies, predict the incidence and indicate their causes. The improvement of the existing recommended standards will improve the quality of preventive and preventive measures against various types of diseases. It should be noted that all preventive measures should be carried out with strict observance of the rules, starting with pasture maintenance and ending with the stall period. Do not forget about observing the time, timing, seasonality of the use of forage lands, mandatory inspection of livestock and their parking places. One of the primary tasks is the immediate isolation of animals when identifying the primary signs of infection, followed by diagnostic and therapeutic procedures.

The work considers the influence of the morphological characteristics of the AgNPs (form, sizes of silver nanoparticles (AgNPs), the average size of the area) from the composition of the reducing agent and their influence on the optical characteristics and electrochemical activity of the sensor based on the AgNPs to H2O2. The intensity of the optical spectra of absorption AgNPs and the electrochemical activity of the sensors based on them correlate with the size and shape of the particles. It is shown that the greatest electrochemical activity of H2O2 is possessed by AgNPs-based sensors obtained by using sodium citrate. The reason for increasing the electrochemical activity of the sensor based on the AgNPs obtained in the presence of the soft restorer of sodium citrate is an increase in the area of their active surface 1.3–2.7–3.3 μm2 due to the non-spherical form of particles (triangular, prismatic, pyramidal form), compared with spherical particles obtained using borhydridicitrate and borohydride-based reducing agents.

The effect of the shape and size of silver nanoparticles on the electrochemical characteristics of sensors based on them is considered by the example of the hydrogen peroxide (H 2 O 2 ) determination. A sodium-borohydride-based electrochemical sensor yields a one-fold increase in the analytical signal when H 2 O 2 in a concentration of 1 × 10 ‒7 M is added. A sensor based on the finest (0.5–17.5 nm) spherical silver nanoparticles obtained using two reducing agents (sodium borohydride and sodium citrate) simultaneously makes it possible to increase the H 2 O 2 -determination sensitivity by six orders of magnitude (the detection limit is 0.16 × 10 –13 M). The detectable H 2 O 2 -concentration range varies within half an order of magnitude and is (0.8‒3.0) × 10 ‒13 M. A sensor based on silver nanoparticles of various shapes 10‒55 nm in size obtained using sodium citrate also exhibits an increase in the H 2 O 2 -determination sensitivity by six orders of magnitude (the detection limit is 0.74 × 10 –13 M). This sensor has a detectable H 2 O 2 concentration range within an order of magnitude: (1.0‒10.0) × 10 ‒13 M. The causes of the different sensitivities and detectable H 2 O 2 -concentration ranges for the electrochemical sensors are discussed depending on the size and shape of silver nanoparticles. The mechanism of the interaction of adsorbed oxygen with silver nanoparticles on the sensor surface is proposed.

In this article, the veterinary-sanitary examination of animal carcasses with such a disease as scrapie is considered. For our country, this disease is quite exotic, and at the same time topical. The exoticism is due to the fact that scrapie is not so widespread. The actuality lies in the fact that this disease does not manifest itself immediately and there are no clear clinical manifestations, this disease cannot be diagnosed for a long time. These factors introduce significant doubts into the quality of livestock products received from the manufacturer, which must be taken into account during veterinary-sanitary examination in laboratories. To estimate the state of health and predict the quality of sheep slaughter products, great importance should be given to the study of changes in patterns in clinical, anamnestic, morphological, metric and anatomical indicators of the animal organism. The use of these indicators will reveal certain patterns that will form the basis of a number of rules for modern veterinary-sanitary assessment of animal slaughter products. Identification of infected animals for scraping occurs in the last stages. This can be related to the fact that the course of the disease passes covertly for a long time and there are no obvious clinical, anamnestic, morphological, metric and anatomical changes. That creates certain threats not only for livestock population, since the disease is transmitted from animals to each other, but also for people, because the transmission of pathogens from the animal to human is possible.

The work is devoted to assessing the quality of livestock slaughter products, taking into account skin diseases of various etiologies. This criterion sometimes makes a significant contribution to the quality of livestock products, so it must be taken into account during veterinary and sanitary examination in laboratories. To assess the state of health and predict changes in the quality of products of the slaughter of sheep, great importance belongs to the study of patterns in the clinical, anamnestic, morphological, metric, and anatomical indicators of the body of the sheep. The use of these patterns and their dynamic changes characteristics helps to find out certain patterns that made it possible to develop several rules for the modern veterinary and sanitary assessment of sheep slaughter products. These rules allow not only to indicate the premisses for the occurrence of dermatitis of various etiologies but also to improve existing developments, as well as improve the quality of preventive remedies to prevent and eliminate these types of diseases. It should also be noted that for the start of preventive steps, the strict observance of elementary rules is important when grazing the number of sheep. This includes their movement in compliance with certain periods, the seasonality of the use of forage land, and the mandatory inspection of the livestock of animals and their parking places. In the case of the detection of infected animals with signs of damage to the skin, the animals are immediately isolated with subsequent diagnosis and treatment.

This paper discusses the use of feed additives with the addition of amino acids containing methionine and cysteine. To study the effectiveness of the use of feed additives, one of the main functional systems of the body of any animal, blood, was monitored. In confirmation, blood samples were taken for hematological and biochemical examination. It is shown that in the first months of use there is an increase in the weight of ducks, and in the period of egg production there is a decrease in productivity. Reduced productivity is associated with the preparation and restructuring of the body for egg production. New approaches to the development of feed additives are needed to assess the state of health and predict the quality of products. Great importance is given to standard methods of studying and identifying certain patterns in the clinical, anamnestic, morphological, metric and anatomical parameters of the bird body.

Portable electrochemical sensors based on noble metal nanoparticles (МеNPs) for the quantitative determination of hydrogen peroxide (H2O2) and sulfur-containing amino acids (cysteine, methionine, glutathione) are discussed. These sensors have high sensitivity (pM), with low sample requirements (<50 μl). This article discusses methods for producing sensors based on silver and gold nanoparticles and their application in voltammetry. It is shown that the sensitivity of H2O2determination on a sensor based on silver nanoparticles (AgNPs) depends on their size. Their size is determined by the reducing agent. Sensors based on AgNPs of spherical shape with the smallest size from 0.5 to 17.5 nm have the highest sensitivity for determining H2O2, but a narrow range of determined concentrations. Sensors on medium-sized AgNPs have optimal metrological characteristics. Their size is from 10 to 55 nm, less sensitive, but with a wide range of determined concentrations from 0.1 to 1 nm H2O2. The linearity of the range of glutathione concentrations is 1.0-10.0 pM. The linearity of the range of determined concentrations of methionine is 1–26 рМ.

In this paper, we consider the control of animal carcasses and the detection of such a disease as scrapie. For our country, this animal disease remains quite rare, but at the same time it should not be overlooked. This is due to the fact that there are regular purchases of breeding cattle from abroad, and this is a risk of importing an infected animal. The relevance of the work is that the disease of sheep and goats-scrapie can not be detected at very early stages of its development. Symptomatic manifestations do not appear immediately, there are no clear clinical characteristics, which is why this disease can not be diagnosed for a long time. To assess the health status and predict the quality of products obtained, new approaches are needed to study the products of sheep and goat slaughter. Great importance is given to standard methods of studying, identifying certain patterns in clinical, anamnestic, morphological, metric and anatomical indicators of the animal body. Using these indicators and changing their dynamic characteristics, it is possible to make significant adjustments in the definition of this disease, which would allow us to develop a number of rules for modern veterinary and sanitary evaluation of animal slaughter products.

The second for the significance livestock sector is pig breeding, which accounts for one-third of the country’s meat production. Long-term world practice of pig farming confirms the high maturity of this species of animals, excellent taste, nutritious meat and most importantly the ability to quickly increase food production, and thereby ensure the optimal balance of the diet of the population. One of the constraining factors for the development of this industry is the development of iron deficiency alimentary anemia in pigs during the first 7 days of animal life, which affects the growth, development and increase of live weight in animals. Without preventive measures to supplement the iron with animals, up to 100% of piglets become sick with anemia, which can lead to the death of a significant part of the young population. This article presents the results of the toxicological approbation of a new iron-containing preparation for farm animals. The question of finding a less toxic iron preparation with a higher prolonging effect is relevant.

The intensity and direction of the living organism’s metabolic processes determine the growth rate, development, nutrients synthesis, as well as the reproductive body function and the biosynthesis of proteins, fats and carbohydrates in the form of feedstuff and raw materials. The higher animals’ productivity, the more intensive are metabolic processes. The living bodies’ metabolism proceeds with a certain speed and at the same time contrariwise, but with accurate coherence and interaction due to the participation of “life regulators”, enzymes, which represent the specific proteins, the activity of which is regulated by hormones, vitamins and various synergistic elements. Chemical elements included in the living organism structure are not synthesized in it but must be originated from feeds and other nutrients. Changes in essential micronutrients supply shall not be studied in isolation from the general bio-geochemical situation. Both excess and deficiency may lead to metabolic disorders involving enzyme systems. Knowledge applied by veterinary specialists about the imbalance of various chemical elements in soil, water and feeds has formed the basis for raising the issue of endemic animal diseases diagnosis and prevention. The feeds inadequacy often leads to undernutrition and the reduction of their value in the stall period, which causes the fatness reduction and, therefore, the decrease in mobility and activity, and the weakness of animals. General inspection and palpation of animals reveal ruffled coat, dry-looking and non-supple skin, and if the lack of nutrients becomes more intense, anemic mucous membranes (in more complicated forms even cyanosis and icterus) are observed.

The research deals with determination of low levels of hydrogen peroxide in objects of technogenic and geological origins. The aim of the work was to develop a sensitive sensor based on silver nanoparticles to detect hydrogen peroxide in water objects. Objects: artesian and rainwater collected in the city and suburbs. Methods: voltammetry, transmission microscopy. Results. The shape, size and amount of silver nanoparticles depend on the nature of the reducing agent. When using two reducing agents of borohydride and sodium citrate, the smallest spherical particles - from 0,5 to 17,5 nm, are obtained. When using sodium citrate, larger silver nanoparticles - from 10 to 55 nm, in various shapes are obtained. They are as follows: rod-shaped, prismatic, triangular with a particle size from 10 to 55 nm. AgNPs-Bg have a rod-like and prismatic shapes 5-65 nm in size, connected in chains, i. e. agglomerated. The mechanism of electrochemical processes of silver nanophase transition on the surface of graphite electrode to 0,1 M NaOH in the presence of various reducing agents is proposed. This mechanism does not depend on the nature of the reducing agent. A feature of electroreduction of silver nanophase obtained in the presence of citrate potassium is the reduction of silver ions from the complex ions [Ag(OH)(2)](-). The authors have proposed the mechanism of electrochemical transition processes of silver nanophase in the presence of various reducing agents. It was found that the cathode maxima at E-c=0,08 V corresponds to hydrogen peroxide reduction. Using a sensor based on the silver nanoparticles obtained in the presence of sodium citrate the dependence of the current of the maximum on hydrogen peroxide concentration was linear - in the range from 0,1-1 nM, and the detection limit was 0,087 nM. The content of hydrogen peroxide in rain and artesian water was determined. The proposed sesor modified by silver nanoparticles obtained in presence of sodium citrate is simple, rapid, and sensitive. This sensor has a wide range of concentrations for determination of hydrogen peroxide.

Актуальность работы связана с необходимостью определения низких содержаний пероксида водорода в объектах техногенного и геологического происхождения. Цель: разработать сенсор с повышенной чувствительностью на основе наночастиц серебра для контроля окружающей среды и определить концентрацию пероксида водорода в водных объектах. Объекты: артезианская и дождевая вода, собранная в черте города и пригорода. Методы: просвечивающая электронная микроскопия, вольтамперометрия. Результаты. Форма и размер наночастиц серебра зависят от природы восстановителя. При использовании двух восстановителей боргидрида и цитрата натрия получают частицы сферической формы наименьшего размера – от 0,5 до 17,5 нм. При использовании цитрата натрия получают наночастицы серебра большего диаметра – от 10 до 55 нм, различной формы: сферические, призматические и треугольные. Наночастицы серебра, полученные с использованием боргидрида натрия, агломерированы в цепочки размером до 65 нм. Особенностью электровосстановления нанофаз серебра, полученных в присутствии цитрата натрия, на поверхности графитового электрода в 0,1 М NaOH является восстановление ионов серебра из комплексных соединений [Ag(OH)2]–. Предложен механизм электрохимических процессов перехода нанофаз серебра, полученных с использованием различных восстановителей. Этот механизм не зависит от природы восстановителя. Установлено, что катодный максимум при Ек=0,08 В соответствует процессу восстановления пероксида водорода. Зависимость катодного максимума от концентрации пероксида водорода, полученного с использованием сенсора на основе наночастиц серебра в присутствии цитрата натрия, была линейной в диапазоне от 0,1 до 1 нМ, предел обнаружения составил 0,087 нМ. Определена концентрация пероксида водорода в дождевой и артезианской воде. Предложен простой чувствительный сенсор на основе наночастиц серебра, полученный с использованием восстановителя цитрата натрия. Этот сенсор имеет широкий диапазон концентраций для определения пероксида водорода.

We have developed an ointment preparation consisting of silver and zinc oxide nanoparticles, which form the basis of the nanocomposition. This drug can reduce the healing time of the wound surface due to the inclusion of nanodispersed particles in the composition. Application of nanoparticles allows to reduce inflammatory process, to carry out disinfecting treatment of a wound surface from pathogenic microorganisms, and accordingly to create optimum conditions for reparative process. Nanocomposite preparation has many advantages over existing analogues without irritating and allergic effects. Due to the high adsorption capacity, it allows to accelerate the healing process of the damaged surface of the skin. Initial studies were conducted on laboratory rats at the age of 6 months with a close mass that was up to 250 g in accordance with international requirements for the use of laboratory animals. As a result of the experiment, a new ointment preparation based on silver and zinc oxide nanoparticles, which are active components of the nanocomposition, was obtained. The use of these components allowed to accelerate the process of reparative restoration of the skin with full recovery of the studied animals. As shown by the experience, the recovery rate on average accelerated by seven days, compared with similar drugs available on the pharmaceutical market.

The research deals with the need to determin palladium content in copper-nickel sulfide ores, copper sludges, nickel concentrates in the presence of gold in order to study new deposits of noble metals and calculate their reserves, and to determine as well the content of palladium in waste from various industries. The aim of the work was to find the optimum conditions of palladium determination in the presence of gold in copper-nickel sulfide ores, copper sludges, nickel concentrates and to eliminate its interfering influence in palladium voltammetric determination. The methods: stripping voltammetry, atomic adsorption spectrometry, transmission electron microscopy. Results. The authors have defined optimum conditions of palladium determination in ores after ultraviolet irradiation in the presence of oxalic acid. They are as follows: graphite indicator electrode, E-acc= -0,9 V, t(acc)=120 s, v=0,08 V.s(-1). The authors developed the method for determining palladium in gold-bearing ores. The method eliminates the interfering effect of gold without changing the linear dependence of height of anodic maximum of palladium ions on its concentration. Furthermore, palladium voltammetry determination time reduces by three times compared to the standard procedure. The current research has shown that reduction of gold compounds with ultraviolet irradiation occurs to elemental gold in the form of fractal structures. It is demonstrated that the anodic maximum height of palladium ions increases linearly when its concentration changes from 0,1 to 1000 mg.l(-1). The proposed analytical method has satisfactory metrological characteristics. The accuracy factor of the palladium determination is from 30 to 42 % by stripping voltammetry. It is equal to 13-36 % by atomic adsorption spectrometry.

Summing up domestic and foreign experience in sheep housing and feeding, practical proposals have been drafted on effective sheep feeding arrangement aimed at dermatitis prevention. Chemical elements included in the living organism structure must be originated from feeds and other nutrients. There is a concept of essential elements, i.e. the elements which are deeply involved in the biochemical processes of the living body. Changes in essential elements supply shall not be studied in isolation from the general bio-geochennical situation. The feeds balanceness according to the sheep needs in the stall period makes it possible not only to obtain a high product quality but also to prevent some disorders. Both excess and deficiency may lead to metabolic disorders involving enzyme systems. Knowledge applied by veterinary specialists about the imbalance of various chemical elements in soil, ater and feeds has formed the basis for raising the issue of endemic animal diseases diagnosis and preventic respect to amino acids, macro-and micronutrient Diet formulation must provide the balanceness with contribute to more appropriate activation of physiological mechanisms responsible for barrier functions regulation and increasing resistance to adverse external factors. The deficiency of macro-'and micronutrients in the animal organism leads to morphological, biochemical and physiological changes of the skin cover. The summation of pathological changes is observed in timing aspect. The deficiency of macro-and micronutrients leads to the slow (prolonged) changes. In these conditions the summation of all changes takes place, thus giving rise to the pathological process. The skin loses its resilience and elasticity and becomes calloused. The process deepens by the stalling, as the metabolism decreases, and the amount of incoming nutrients declines. Consequently, the imbalanced feeding diet leads to the aggravation of nutrients deficiency, anemic mucous membranes (and in more complicated forms even cyanosis and icterus) are observed.

Background: Glutathione (GSH) is a water-soluble tripeptide which is contained in biological fluids (blood plasma, cell fluid) and plays an important role in redox processes in the organisms of humans and animals. The lack of GSH leads to oxidative stress in living cells and causes dangerous diseases. In this regard, the development of rapid and simple analytical methods to determine GSH in biological fluids is an important task. The purpose of the present paper was to explore the possibility of electrochemical determination of GSH using AuNPs-modified graphite electrodes to develop a sensitive voltammetric method.Methods: Electrochemical sensor (AuNP-GCE) for the determination of GSH in solutions was prepared by deposition of gold nanoparticles (5-15 nm) from Au-hydrosol at graphite electrode surface. Composition of electrodes was controlled using scanning electron microscopy and EDX-analysis (JSM 5500). Electrochemical behavior of GSH at graphite-based electrodes in alkaline medium was investigated using cyclic voltammetry (CV) by means of electrochemical analytical device TA-4 (Tomsk, Russia).Results: Electrocatalytic oxidation of GSH at AuNP-GCE occurs at +0.05 V (vs. silver chloride ref. electrode) in 0.1 M NaOH and is revealed from CV as an "inverse" current peak in the cathodic direction of potential scan. The sequence of electrode reactions has been suggested which includes oxidation of Au nanoparticles when potentials scanned towards positive direction up to 0.8 V and consequent GSH electrocatalytic oxidation by Au(I)-oxide during the backward potential scan represented as the "inverse" peak.Conclusion: Au-nanoparticles modified graphite electrode exhibits electrocatalytic activity towards GSH oxidation in alkaline medium. An "inverse" current peak in cathodic part of CVs can be used to determine concentration of GSH in a solution. The current of this peak linearly depends on GSH concentration in the interval 2-14 pM (detection minimum 0.7 pM) in supporting solution 0.1 M NaOH. The proposed method can be applied for determination of glutathione in biological fluids.

It was established that the silver nanoparticles (AgNPs) in an equimolar ratio have the highest electrochemical activity on a graphite electrode (GE) surface in an alkaline medium. The electrocatalytic oxidation mechanism of hydrogen peroxide on the GE surface was proposed. We detected an additional maximum at E = 0.3 V on the cathodic branch of the cyclic curve in the potential range from +2.0 to -1.0 V. The appearance of this maximum indicates the reduction of hydrogen peroxide generated during AgNPs electrooxidation in the potential range from -1.0 to +2.0 V.