Selenium and its compounds – Determination of total selenium in urine by ICP-MS

The working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area developed and verified the presented biomonitoring method. Selenium is used in different industrial processes. In the workplace, employees are mainly exposed to elementary selenium and inorganic selenium compounds. In contrast, the non-occupationally exposed general population ingests mainly organic selenium compounds, like selenomethionine and selenocysteine, via the diet. Following exposure, selenium can be determined in serum/plasma and in whole blood/erythrocytes. While the selenium concentrations in these matrices reflect exposure from recent weeks or even months, urinary selenium concentrations are suitable for the determination of short-term exposure (e.g. of the last shift). The aim of this work was to develop a selective method for the determination of total selenium in urine while avoiding the selenium enhancement effect caused by volatile selenium species (e.g. dimethyl selenide or dimethyl diselenide). The method has been comprehensively verified, and the reliability data have been confirmed by replication and verification of the procedure in a second, independent laboratory. Urine samples are mineralised by microwave-assisted digestion using an acidic hydrogen peroxide-containing solution, thereby converting the various selenium species present in the urine into selenite. The selenium concentrations in the diluted digestion solutions are determined by mass spectrometry with inductively coupled plasma (ICP-MS) on m/z = 78. Germanium is used as internal standar

Bisphenol A, Bisphenol F und Bisphenol S – Bestimmung von Bisphenol A, Bisphenol F und Bisphenol S in Urin mittels UPLC-ESI-MS/MS

The working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area developed and verified the presented biomonitoring method. Bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS) are co-monomers for producing engineering plastics used in the automotive, food, and household sectors and are also used in paper chemicals and leather-tanning agents. Due to the wide range of applications, exposure to these bisphenols can occur both at the workplace and via the environment. The aim of this work was to develop a selective method for the determination of BPA, BPF, and BPS in human urine. This method has been comprehensively verified, and the reliability data have been confirmed by replication and validation of the procedure in a second, independent laboratory. The internal standards are added to the buffered urine samples, which are then subjected to enzymatic hydrolysis and processed via dispersive liquid-liquid microextraction (DLLME). The analytes are separated from matrix components by liquid chromatography and detected by tandem mass spectrometry using electrospray ionisation. Quantitative evaluation is carried out via external calibration in water. The good precision and accuracy data show that the method provides reliable and accurate measurement values. The method is selective and sensitive, and the quantitation limits of 0.25 μg/l, 0.10 μg/l, and 0.05 μg/l urine for BPA, BPF, and BPS, respectively, are sufficient to determine occupational as well as background exposur

Bisphenol A, bisphenol F, and bisphenol S – Determination of bisphenol A, bisphenol F, and bisphenol S in urine by UPLC-ESI-MS/MS

The working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area developed and verified the presented biomonitoring method. Bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS) are co-monomers for producing engineering plastics used in the automotive, food, and household sectors and are also used in paper chemicals and leather-tanning agents. Due to the wide range of applications, exposure to these bisphenols can occur both at the workplace and via the environment. The aim of this work was to develop a selective method for the determination of BPA, BPF, and BPS in human urine. This method has been comprehensively verified, and the reliability data have been confirmed by replication and validation of the procedure in a second, independent laboratory. The internal standards are added to the buffered urine samples, which are then subjected to enzymatic hydrolysis and processed via dispersive liquid-liquid microextraction (DLLME). The analytes are separated from matrix components by liquid chromatography and detected by tandem mass spectrometry using electrospray ionisation. Quantitative evaluation is carried out via external calibration in water. The good precision and accuracy data show that the method provides reliable and accurate measurement values. The method is selective and sensitive, and the quantitation limits of 0.25 μg/l, 0.10 μg/l, and 0.05 μg/l urine for BPA, BPF, and BPS, respectively, are sufficient to determine occupational as well as background exposure

Государственное регулирование электроэнергетики

Цель работы – разработка теоретических и практических положений, направленных на совершенствование механизмов государственного регулирования электроэнергетики в России, выявление основных тенденций и возможных путей дальнейшего развития названной сферы в российской экономике. Объектом исследования являются отношения, возникающие в процессе осуществления государственного регулирования электроэнергетической отрасли в России.Purpose - to develop theoretical and practical provisions aimed at improving the mechanisms of state regulation of electric power industry in Russia, identifying the main trends and opportunities for further development of the said spheres of the Russian economy. The object of the study are the relations arising in the implementation of state regulation of electric power industry in Russia

Glyphosate – Determination of glyphosate and AMPA in urine by GC-MS/MS

The working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area developed and verified the presented biomonitoring method. Glyphosate (N-phosphonomethylglycine) is a synthetic phosphonic acid derivative which has been used as a broad spectrum herbicide since 1974. Its only known metabolite is aminomethylphosphonic acid (AMPA). Exposure in occupational settings is predominantly due to inhalation and dermal contact with glyphosate. The general population is exposed to glyphosate and AMPA via both dietary (plant and animal products) and environmental (soils, surface water, and groundwater) exposure. The aim of this work was to develop a selective method for the determination of glyphosate and AMPA in urine. The method has been comprehensively validated, and the reliability data have been confirmed by replication and verification of the procedure in a second, independent laboratory. The analytes are directly derivatised in the dried urine sample with trifluoroacetic anhydride and trifluoroethanol without an initial extraction step. Calibration is performed using aqueous calibration standards processed analogously to the samples. As internal standards, glyphosate-d2 and 13C,15N-AMPA are added to the urine samples and calibration standards. The derivatives are measured after capillary gas-chromatographic separation with tandem mass-spectrometric detection (GC-MS/MS) using negative chemical ionisation (NCI). The good precision and accuracy data show that the method provides reliable and accurate analytical results. The method is both selective and sensitive, and the quantitation limit of 0.1 μg/l urine for glyphosate and AMPA is sufficient to determine occupational exposure as well as higher background levels in the general populatio

Плазменное нанесение керамических покрытий на детали ядерных энергетических установок

На наружную поверхность силовой герметичной оболочки РИТ наносится защитное покрытие, состоящее из следующих слоев W, Al2O3, MoSi2. Необходимость применения керамического покрытия на внешней оболочке РИТ из жаропрочных материалов объясняется коррозионной, окислительной стойкостью данных покрытий в условиях потенциальных аварий РИТЭГ. Метод нанесения керамического покрытия – плазменный, с помощью электродугового плазмотрона с газовихревой стабилизацией дугового разряда.A protective coating consisting of the following layers W, Al2O3, MoSi2 is applied to the outer surface of the power sealed shell of RIT. The need to use a ceramic coating on the outer shell of a radioisotope heat source from heat-resistant materials is explained by the corrosion, oxidative resistance of these coatings in the conditions of potential accidents of RTG. The method of applying ceramic coating is plasma, using an electric arc plasma torch with gas-vortex stabilization of the arc discharge

Selen und seine Verbindungen – Bestimmung von Selen (gesamt) in Urin mittels ICP-MS

The working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area developed and verified the presented biomonitoring method. Selenium is used in different industrial processes. In the workplace, employees are mainly exposed to elementary selenium and inorganic selenium compounds. In contrast, the non-occupationally exposed general population ingests mainly organic selenium compounds, like selenomethionine and selenocysteine, via the diet. Following exposure, selenium can be determined in serum/plasma and in whole blood/erythrocytes. While the selenium concentrations in these matrices reflect exposure from recent weeks or even months, urinary selenium concentrations are suitable for the determination of short-term exposure (e.g. of the last shift). The aim of this work was to develop a selective method for the determination of total selenium in urine while avoiding the selenium enhancement effect caused by volatile selenium species (e.g. dimethyl selenide or dimethyl diselenide). The method has been comprehensively verified, and the reliability data have been confirmed by replication and verification of the procedure in a second, independent laboratory. Urine samples are mineralised by microwave-assisted digestion using an acidic hydrogen peroxide-containing solution, thereby converting the various selenium species present in the urine into selenite. The selenium concentrations in the diluted digestion solutions are determined by mass spectrometry with inductively coupled plasma (ICP-MS) on m/z = 78. Germanium is used as internal standard. The microwave-assisted digestion allows for the accurate quantification of total selenium in urine even when volatile selenium species are present in the samples