Determination of piroxicam in pharmaceutical based on an oscillating chemical reaction

A novel procedure for kinetic determination of piroxicam (PX) by the concentration perturbations of the Bray-Liebhafsky (BL) oscillatory chemical system was proposed. The response of the BL matrix in a stable non-equilibrium stationary state close to the bifurcation point, to the perturbation by different concentrations of PX, is followed by a Pt-electrode. Under the optimized reaction conditions, the linear relationship between maximal potential shift ΔEm, and PX concentration was obtained in the concentration range 6.8 × 10−5 mol L−1 − 1.7 × 10−3 mol L−1 with a detection limit of 3.5 × 10−5 mol L−1 . The method had a rather good sample throughput (ST) of 45 samples h−1 with the recovery RCV = 103.7 %. Applicatibility of the proposed method to the direct determination of PX in pharmaceutical formulation (injections) was demonstratedPhysical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Level of 90Sr in sediments of the Danube River at the border profile Serbia-Hungary

The radioactive fission product 90Sr has a sufficient half-life time (28.8 y) to be detected for a long time after it appeared in the environment. This radionuclide emits a β-particle of 546 keV, giving progeny to 90Y, also a β-emitter (T1/2 = 64.2 h, 2.28 MeV), with which it reaches secular activity equilibrium for a 14 days. Due to properties, radiostrontium may be considered as a highly hazardous anthropogenic radionuclide. The worldwide presence of 90Sr has been caused intentionally or accidentally in the period between 1950 and 1970, as a consequence of various human nuclear activities. The 90Sr determination is an important part of the annual plan of the radioactivity survey in environmental samples such as soil, sediment, grass, milk, wheat, foodstuff (especially vegetables). A potential contaminant of the Danube River ecosystem (in a radioactive sense) is the Paks Nuclear Power Plant, located in Hungary, 85 km from the Serbian-Hungarian border. Hence, this paper has been given insight to the results of investigation of 90Sr content in sediment of the Danube River at border profile between Serbia and Hungary. Sediment samples were collected a few times of year at Serbian side of the Danube River (left coast) in Bezdan. Within the mentioned ecosystem sampling was classified into four zones (sampling points), the first at 1425.5 km river flow, the second at 1426.3 km river flow, the third at 1427.2 km river flow and the fourth at 1428 km river flow. In the each zone one sample is collected. The preparation and analysis of collected samples were performed in Laboratory for Radiation Measurements of the Vinča Institute for Nuclear Sciences. The study covered a period of six years from 2016 to 2021. The level of activity of radionuclide of interest was determined by the radiochemical analytical method of 90Sr determination via its short-lived daughter 90Y. The samples after applied radiochemical procedure were counted by low-level gas proportional counter Thermo Eberline FHT 770T (ESM Eberline Instruments GmbH, Erlangen, Germany). The counting time was 5400 s. The counting efficiency of this counter was 35 % for the β-particle of 90Y. The measured values of 90Sr activity concentration in sediment samples of the Danube River were ranged between 0.18 Bq/kg and 0.79 Bq/kg for dry matter, depending on the sampling season or sampling point. The values of 90Sr activity concentration in investigated samples were far below level before starting work of the Paks Nuclear Power Plant (7.1 Bq/kg of dry matter). Evaluation of the accuracy of the applied method was confirmed using reference material and interlaboratory comparison samples. The results of this study were compared to the values available from the literature and the comparison confirmed that no significant contamination of investigated ecosystem in terms of the content of anthropogenic radionuclide 90Sr. The conducted study points out the importance of systematic testing of the content of anthropogenic radionuclide 90Sr in sediments as an important element in the system of control and testing of environmental safetyX JUBILEE International Conference on Radiation in Various Fields of Research : RAD 2022 (Summer Edition) : book of abstracts; July 25-29, 2022; Herceg Novi, Montenegr

Perturbation of the Dushman reaction with piroxicam: experimental and model calculations

A novel method for the determination of piroxicam (PX) is proposed and validated. For this purpose, the Bray-Liebhafsky (BL) non-oscillating subsystem (mixture KIO3 and H2SO4), i.e. Dushman reaction (DR) was used. The proposed method relies on the linear relationship between maximal potential shift, ΔEm, and the logarithm of the injected PX amounts in the concentration range 2.0 × 10−5 mol L−1 − 2.0 × 10−4 mol L−1 . The sensitivity of the proposed method is 1.5 × 10−5 mol L−1 . Some aspects of the possible mechanism of UA action on the DR matrix system are discussed.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Radioactivity Concentrations in Spa Waters - Dose Assessment

In this study 6 different spa water samples from Serbia, Hungary and Czech Republic were investigated in order to determine their radioactivity concentrations. These waters have been used on a large scale for medical and bathing purposes; for therapy, rehabilitation and recreation and also used for drinking, which is the most important. The obtained results showed that natural activity concentrations of alpha emitting radionuclides was within World Health Organization recommended levels and Serbian applicable regulations, but the gross beta activity exceed 1 Bq L-1 for some of the samples. Considering the fact that gross beta activity in four samples was higher than recommended levels, gamma spectrometric measurements were performed, in order to identify radionuclides which caused increase of the gross beta activity. It was found that K-40 was responsible for the elevated gross beta activity. Based on the obtained results the annual effective dose was calculated.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr

Radioactivity of 137Cs in mushrooms

10. međunarodni skup "Sigurnost i kvalitet hrane" : Maj 13. 2022

Comparison of two different methods for gross alpha and beta activity determination in water samples

Measurement of the gross alpha and beta activity concentrations in various matrices is suitable as a preliminary screening procedure to determine whether further analysis related to specific radionuclide is necessary. In Serbia, according to current regulations, radioactivity concentrations in drinking water for gross alpha and gross beta should be LT 0.5 and LT 1.0 Bq L-1, respectively. The generally accepted methods for gross alpha and beta activity analysis of drinking water in different countries are: EPA 900.0 and ISO methods (ISO 9696, water quality - measurement of gross alpha activity in non-saline water - thick source method, and ISO 9697, water quality - measurement of gross beta activity in non-saline water). This paper describes comparison of preparations and measurement gross alpha and beta activity in bottled mineral waters as well as in tap waters in Serbia using two methods: EPA 900.0 with and without ash, and ISO methods. Concentration of total dissolved solids (TDS) in investigated water samples was determined. Based on obtained TDS, certain volume was evaporated. The instrumentation used to count the gross alpha and gross beta activities for both methods is alpha/beta low level proportional counter Thermo Eberline FHT 770 T

Quality control of HPGe detectors for gamma spectrometry of environmental samples

Quality assurance and quality control (QA/QC) is a series of procedures aimed at verifying the validity of the measurement results and are defined in the Standard ISO 17025/17. QC should be planned, described in the quality control documentation, performed in a systematic manner, recorded and reviewed. All proposed measures for QC/QA are implemented in the Radiation and Environment Protection Department of Institute for Nuclear Sciences Vinča, Belgrade. One of these procedures prescribes a regular quality control of the instruments used for the measurement. In this paper, the quality control of three High Purity Germanium (HPGe) detectors, produced by Canberra, are presented. The accuracy and reproducibility of gamma spectrometry systems are verified on a weekly basis. Total background count rate is used to verify that the detector and shield has not been contaminated. Measurement of the total activity of calibration source is used to check the efficiency calibration and general operating parameters of the system such as peak shape and peak drift. These values are observed and verified if they are within the acceptance limits. For that purpose, 60Co and 133Ba point sources, produced by Czech Metrology Institute and traceable to Bureau International des Poids et Mesures (BIPM), are used. The acceptance limits for each controled parameter are defined according to the statistical analysis of the previous QC period. The acceptance limits are set to be ±2σ and ±3σ of the mean value taken over a previous year. Results of the QC measurement falling between ±2σ are considered to be satisfactory, the ones between ±2σ and ±3σ are warning and those exceeding ±3σ indicate that a problem with the measurement system has occurred. Analysing the QC data acquired for 2021, we can conclude that major part of parameters were within the limits of acceptance. Occasional discrepancies were minor and were addressed immediately. Discrepancies of the peak shape were corrected simply by additional cooling of the instrument, peak position by performing an energy calibration and background was corrected by ventilating the laboratory.Twentieth Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 30 – December 2, 2022, Belgrade, Serbi

Natural and artificial (90Sr) radionuclides in some carbonated mineral waters used in Serbia

A radiological characterization of 7 different carbonated mineral water samples collected in the local supermarkets in the area of Belgrade (produced in Serbia) was carried out. Analysis included determination of gross alpha and gross beta activities. The obtained results showed that the natural activity concentrations of alpha and beta emitting radionuclides in carbonated mineral water samples were within World Health Organization recommended levels, except for the Heba Strong and Kiseljak samples where the beta activity exceeds 1 Bq/L. For these two water samples gamma spectrometry analysis was performed as well as determination of 90Sr by oxalic method. The instrumentation used to count the gross alpha and gross beta activities, as well as for 90Sr, was a/b low level proportional counter Thermo Eberline FHT 770 T. Gamma spectrometric measurements were performed using a HPGe Canberra detector with a counting efficiency of 20%. The annual effective dose equivalent due to ingestion of investigated waters was calculated for age group >17, and obtained values are lower than 0.1 mSv recommended reference level. Finally, a comparison of the investigated waters with worldwide data was made. [Projekat Ministarstva nauke Republike Srbije, br. III43009

Radiochemical bioassay on Am-241 traces for internal contamination evidence

Americium-241 is an artificial transuranic radionuclide with high specific activity of 0.13 TBq/g and long half-life T1/2=432.2 years. Besides the nuclear and space industries it has a wide application in non-destructive testing, as a thickness gauge and in smoke detectors. Due to a high radiotoxicity surpassing its chemical toxicity a long-term internal contamination by low americium quantities may be a serious health issue. We have developed a bioassay procedure for americium-241 tests for persons occupationally exposed to risk of americium intake by inhalation and ingestion. The procedure is suitable for low-level activities determination and it includes decomposition and preconcentration of complex organic samples, precipitation of lantanide group elements, followed by selective multiple solvent extractions and acid/alcohol-based separations using the anion-exchange (DOWEX resin) chromatography. Optimization of the acidity of alcohol solutions especially for final fraction eluation was the crucial step in this procedure. The concentration measurements may be performed by ICPMS immediately, while in the case of alpha spectrometry using properly calibrated PIPS detectors, thin layer americium alpha sources had to be prepared by modified Talvitie’s electroplating procedure prior to activity measurements. The efficiency of the proposed radiochemical separation procedure had been evaluated by the Am-243 tracer addition and it exceeded 30% that is quite good in compare with other reported values. On the contrary, the electroplating efficiency was about 50% that is significantly low if compared with over 90%, reported for uranium and thorium, probably due to a low distribution coefficient for trivalent Am against lanthanides. It has consequences on the thickness of the alpha source and measurement efficiency. The advantage of the procedure is high sensitivity but issues with selectivity may be avoided by using ICPMS measurement technique instead of alpha-spectrometry in order to avoid electrodeposition step and time consuming activities counting. This procedure may be recommended in cases when there is a doubt on systematic low-level internal contamination so that operational procedures may be modified accordingly, and the workers awareness and risk perception affected. The internal dose assessments based on the bioassay results on Am-241 contents in analyzed samples may be assessed using available biokinetic models.VIII International Conference on Radiation in Various Fields of Research : RAD 2020 : book of abstracts; Virtual Conferenc

Physico-chemical characterization and tritium activity determination in spring waters

The quality of drinking water should be monitored and analyzed with the aim of determination of water pollution and to minimize health hazards. From a radiological point of view, drinking water may contain natural and artificial radionuclides. One of the radionuclides that can occur in drinking water is tritium. Tritium, as the only radioactive isotope of hydrogen, occurs naturally as a cosmogenic radioisotope in the stratosphere but also has an anthropogenic origin. This study presents the results of some physico-chemical analysis and tritium activity determination carried out for natural water sources in the vicinity of Smederevska Palanka. Water samples from eleven natural water sources were analysed: (source “Veliki Sipovac” (Azanja), source “Pinosava” (Kusadak), source “Vrelo” (Glibovac), source “Vidovača” (Vodice), source “Mineral water” (Vodice), source “Mineral water” (Cerovac), source “Sveta Trojica” (Cerovac), source “Šiljakovac” (Ratari), source “Klis” (Golobok), source “Palanački Kiseljak” (Smederevska Palanka), source “Sveta Petka” (Smederevska Palanka)), in order to determine possible contamination, because the local population is supplied with drinking water from these springs. Physico-chemical characterization was performed measuring pH, total dissolved solids (TDS) and conductivity. The pH values were measured using InoLab pH meter WTW with glass electrode SenTix 81. The conductivity of the samples was measured using Conductometer InoLab WTW Cond7110 at 20°C. TDS measurement was based on the weight of the solid residue remained after evaporation of 40 ml of sample and subsequent drying at 105°C. For tritium activity determination samples were distilled and electrolytically enriched using direct current source SORENSEN DCR60-B30. After electrolytic enrichment samples were measured by Ultra Low Level Liquid Scintillation Spectrometer Quantulus 1220. Conductivity and pH were measured before and after distillation of water samples. Some of investigated waters are naturally acidic and measured values for pH and conductivity show different results for samples before and after distillation. TDS has a higher value for natural mineral waters. In accordance with the legislation in the Republic of Serbia elevated tritium levels in water samples may indicate the presence of other artificial radionuclides. If tritium concentration exceeds allowed value, additional analysis is required. In that case it is necessary to perform gamma spectrometric analysis of the content of artificial radionuclides or analysis of 90Sr. The permissible value of tritium in drinking water is 100 Bq/l. All analyzed waters in this study meet the legal regulations and from the radiation point of view can be used for drinking. The annual effective dose was calculated based on the tritium concentration in the investigated samples for different age groups. The obtained results are in accordance with legislation.X JUBILEE International Conference on Radiation in Various Fields of Research : RAD 2022 (Spring Edition) : book of abstracts; June 13-17, 2022; Herceg Novi, Montenegr