Determinació del contingut d’almagat en un antiàcid mitjançant una volumetria complexomètrica

Aquest document descriu tres procediments analítics per dur a terme la determinació del contingut d’almagat en un preparat farmacèutic mitjançant una volumetria complexomètrica. Els procediments estan adaptats pel seu ús a l’assignatura “Laboratori Bàsic de Química Analítica” del Grau de Ciències Químiques de la Universitat de Barcelona

Analysis of isotopes of plutonium in water samples with a PSresin based on aliquat⋅336

There is a necessity to have techniques capable to perform rapid determinations of specific radionuclides with the aim to provide fast response in emergency situations where a large number of samples need to be measured in a short time. Plastic Scintillation Resins (PSresins) raises as an adequate tool to achieve this purpose and in the present study a methodology to determine plutonium using a PSresin based on Aliquat·336 was developed. Different sample treatments have been studied under acidic conditions with an emphasis on valence adjustment treatment to achieve an effective retention within the PSresin. Under 3 M nitric acid conditions and an iron sulphamate (II) + nitrite valence adjustment, quantitative retention and 100% detection efficiency were achieved. The retention of the different interferences evaluated (238U, 230Th, 241Am, 210Pb and 99Tc) was low and therefore they do not interfere significantly in the determination of plutonium, except for 99Tc. Finally, a stable tracer to calculate the PSresin separation yield was studied, revealing that gold is suitable for this purpose. This procedure was applied to the analysis of spiked sea and river water samples, obtaining errors lower than 10% in their quantification

PSresin for the analysis of alpha-emitting radionuclides: Comparison of diphosphonic acid-based extractants

The analysis of radionuclides is complex, with high economic and time costs. For this reason, there is a need to develop new methods and strategies to reduce these costs. One important group in the analysis of radionuclides is the actinides, which are the main constituents assessed in the total gross alpha together with radium and radon test used to measure radioactivity in drinking water. Moreover, in nuclear dismantling processes, the possible spread of the released radionuclides has to be controlled, which is measured by many techniques, depending on the radionuclides, through scintillation. This work presents a new method to analyse actinides using plastic scintillation resins (PSresins) packed in a solid-phase extraction cartridge. The proposed method combines chemical separation and sample measurement into a single step, reducing the effort, time and reagents required for analysis as well as decreasing the amount of waste generated. The PSresins compared in this study contained three selective extractants based on Methylenediphosphonic acid with different radicals, which has a high affinity for tri-, tetra-, and hexavalent actinides in dilute acids. These extractants were immobilised on plastic scintillation microspheres at a ratio of 1/1:6, producing a retention and detection efficiency of 100% for 241Am, 230Th, Uranium and 238Pu. The retention and detection efficiency were 20% and 100%, respectively, for 210Po and low for 226Ra

Thin film oxide-ion conducting electrolyte for near room temperature applications

Stabilized bismuth vanadate thin films are presented here as superior oxide ionic conductors, for application in solid state electrochemical devices operating near room temperature. Widely studied in the 90s in bulk form due to their unbeatable ionic conduction, this family of materials was finally discarded due to poor stability above 500 °C. Here, we however unveil the possibility of using BiVCuO at reduced temperatures in thin film-based devices, where the material keeps its unmatched conduction properties and at the same time shows good stability over a wide oxygen partial pressure range

Development of an equipment for real-time continuous monitoring of alpha and beta radioactivity in river water

Different regulations require the monitoring of radioactivity in the environment (e.g., 2013/51/Euratom, Real Decreto 314/2016) to protect the environment and the population from abnormal radioactivity presence caused by natural reasons or discharges or accidents in nuclear installations. Nowadays, the monitoring of α- and β-emitting radionuclides is performed discontinuously in laboratories due to the difficulties in applying classical techniques to continuous measurements. This limits the number of samples that can be measured per day, produces high costs per analysis, and introduces a significant delay between the moment of contamination and when it is detected. Plastic scintillation microspheres (PSm) represent a new possibility for continuous measurements because water samples can flow through a bed of PSm connected to a pair of photomultipliers (PMTs), allowing continuous monitoring of the activity. This idea is the basis of the Waterrad detector, which can monitor radioactivity at environmental levels in river water. This paper describes the optimization of a detection cell containing PSm, a detection chamber as well as active and passive shielding. In its final set-up, the Waterrad detector presents a background signal of 0.23 (1) cps and detection efficiencies of 1.86(7)⋅10 5 cps⋅L⋅Bq 1 for 3H, 7.4(8)⋅10 3 cps⋅L⋅Bq 1 for 90Sr/90Y and 5.5(5)⋅10 3 cps⋅L⋅Bq 1 for 241Am. The detection limits in the optimum window for a counting time of 5 h were 490 Bq/L for 3H, 2.3 Bq/L for 90Sr/90Y and 3.0 Bq/L for 241Am. These values indicate that Waterrad can be used as an alarm detector for monitoring radioactivity in water at activity levels similar to those of environmental samples, making it suitable for water or waste surveillance involving a high frequency of measurements

Evaluation of synthesis conditions for plastic scintillation foils used to measure alpha- and beta-emitting radionuclides

Plastic scintillation foils of polystyrene and polycarbonate with a thickness between 45 and 200 μm, have been produced using the solvent evaporation method. PSfoils presented a reproducible thickness (10-20%). PSfoils were characterized by the measurement of 36Cl or 241Am. For 36Cl spectrum is located at medium energies since not all energy is deposited in the scintillator and not all betas interact with the foils. For 241Am the efficiency values are very high and spectrum is a sharp peak located at high energies. 222Rn absorption (LD and K) and desorption capacities of the PSfoils have been also evaluated

Rapid method for radiostrontium determination in milk in emergency situations using PS resin

[EN] This study describes a new and rapid procedure for radiostrontium determination in milk samples based on the use of plastic scintillation resins (PS resins). The proposed method reduces the time of analysis by at least 2 h by combining separation and measurement preparation into a single step and optimizing the pre-treatment steps. The method is robust and reproducible, with good total recoveries (65% on average) and a relative bias for total radiostrontium activity (Sr-89 + Sr-90) below 7%. The minimum detectable activity for 100 mL of milk sample measured for 60 min is about 0.34 Bq L-1. The proposed method can quantify radiostrontium content in 5 h, which makes it suitable for use in emergency situations.The authors are grateful to the Spanish Ministerio de Economia y Competitividad (MINECO) for financial support, under CTM2014-02020 and the Catalan Agencia de Gestio d'Ajuts Universitaris i de Recerca (AGAUR) for financial support, under 2014-SGR-1277. We should also like to thank the Universitat Politecnica de Valencia for finantial support under the "Programa propio para la Formacion de Personal Investigador (FPI) de la UniversitatPolitecnica de Valencia - Subprograma 100.Sáez-Muñoz, M.; Bagán, H.; Tarancón, A.; García, JF.; Ortiz Moragón, J.; Martorell Alsina, SS. (2018). Rapid method for radiostrontium determination in milk in emergency situations using PS resin. Journal of Radioanalytical and Nuclear Chemistry. 315(3):543-555. https://doi.org/10.1007/s10967-017-5682-3S5435553153International Atomic Energy Agency (2015) The fukushima daiichi accident, technical radiological consequences, vol 4. IAEA, ViennaInternational Atomic Energy Agency (2006) Environmental consequences of the chernobyl accident and their remediation: 20 years of experience, Report of the UN Chernobyl forum expert group “environment”, radiological assessment reports Series No. 8, IAEA, ViennaPovinec PP, Hirose K, Aoyama M (2013) Fukushima accident: radioactivity impact on the environment. Elsevier, ChinaCouncil Regulation (Euratom) 2016/52 of 15 January 2016 laying down maximum permitted levels of radioactive contamination of food and feed following a nuclear accident or any other case of radiological emergency, and repealing regulation (Euratom) No 3954/87 and commission regulations (Euratom) No 944/89 and (Euratom) No 770/90Vajda N, Kim CK (2010) Determination of radiostrontium isotopes: a review of analytical methodology. Appl Radiat Isot 68:2306–2326Brun S, Bessac S, Uridat D, Boursier B (2002) Rapid method for the determination of radiostrontium in milk. J Radioanal Nucl Chem 253(2):191–197Maxwell SL, Culligan BK (2009) Rapid method for determination of radiostrontium in emergency milk samples. J Radioanal Nucl Chem 279(3):757–760Kabai E, Hornung L, Savkin BT, Poppitz-Spuhler A, Hiersche L (2011) Fast method and ultra fast screening for determination of 90Sr in milk and dairy products. Sci Total Environ 410–411:235–240International Atomic Energy Agency (2013) Rapid simultaneous determination of 89Sr and 90Sr in milk: a procedure using cerenkov and scintillation counting, analytical quality in nuclear applications no. IAEA/AQ/27, IAEA, ViennaBagán H, Tarancón A, Rauret G, García JF (2011) Radiostrontium separation and measurement in a single step using plastic scintillators plus selective extractants application to aqueous sample analysis. Anal Chim Acta 686:50–56Barrera J, Tarancón A, Bagán H, García JF (2016) A new plastic scintillation resin for single-step separation, concentration and measurement of technetium-99. Anal Chim Acta 936:259–266Lluch E, Barrera J, Tarancón A, Bagán H, García JF (2016) Analysis of 210Pb in water samples with plastic scintillation resins. Anal Chim Acta 940:38–45Santiago L, Tarancón A, García JF (2016) Influence of preparation parameters on the synthesis of plastic scintillation microspheres and evaluation of sample preparation. Adv Powder Technol 27(4):1309–1317Savitzky A, Golay MJE (1964) Smoothing and differentiation of data by simplified least-squares procedures. Anal Chem 36:1627–1639Currie LA (1968) Limits for qualitative detection and quantitative determination. Application to radiochemistry. Anal Chem 40(3):586–593UNE 34829:1983, Determination of the calcium content of milkISO 12081:2010, IDF 36:2010, Milk—Determination of calcium content—titrimetric methodHeckel A, Vogl K (2009) Rapid method for determination of the activity concentrations of 89Sr and 90Sr. Appl Radiat Isot 67:794–796Kabai E, Savkin B, Mehlsam I, Poppitz-Spuhler A (2017) Combined method for the fast determination of pure beta emitting radioisotopes in food samples. J Radioanal Nucl Chem 311:1401–1408Eikenberg J, Beer H, Rüthi M, Zumsteg I, Vetter A (2005) Precise determination of 89Sr and 90Sr/90Y in various matrices: the LSC 3-window approach. LSC2005 Advances in Liquid Scintillation Spectrometry, Radiocarbon, AZ, pp 237–249Kim CK, Al-Hamwi A, Toervenyi A, Kis-Benedek G, Sansone U (2009) Validation of rapid method for the determination of radiostrontium in milk. Appl Radiat Isot 67:786–79

Engineering Transport in Manganites by Tuning Local Non-Stoichiometry in Grain Boundaries

Interface-dominated materials such as nanocrystalline thin films have emerged as an enthralling class of materials able to engineer functional properties of transition metal oxides widely used in energy and information technologies. In particular, it has been proved that strain-induced defects in grain boundaries of manganites deeply impact their functional properties by boosting their oxygen mass transport while abating their electronic and magnetic order. In this work, the origin of these dramatic changes is correlated for the first time with strong modifications of the anionic and cationic composition in the vicinity of strained grain boundary regions. We are also able to alter the grain boundary composition by tuning the overall cationic content in the films, which represents a new and powerful tool, beyond the classical space charge layer effect, for engineering electronic and mass transport properties of metal oxide thin films useful for a collection of relevant solid state devices

SiNERGY, a project on energy harvesting and microstorage empowered by Silicon technologies

Internet of Things and Trillion Sensors are buzzwords illustrating the path towards the next grand paradigm: Smart Everywhere. In many of those realizations long term autonomy of sensor systems is a must to tackle different societal challenges and innovation scenarios. Microenergy autonomy solutions based on energy harvesting offer a promising way in which, KETS mediated, silicon technology and silicon friendly materials may play a decisive role.This work was supported by FP7- NMP-2013-SMALL-7, SiNERGY (Silicon Friendly Materials and Device Solutions for Microenergy Applications), Contract n. 604169Peer reviewe

Proyecto RIMDA-Química. Proyecto institucional de fomento de la calidad docente en la Facultad de Química de la Universidad de Barcelona

Se presenta el Proyecto Institucional de Fomento de la Calidad Docente de la Facultad de Química (Proyecto RIMDA-Química), promovido por el equipo decanal de la Facultad de Química y por el Vicerrectorado de Docencia de la Universidad de Barcelona (UB), en el marco del programa de Investigación, Innovación y Mejora de la Docencia y del Aprendizaje de la UB. El proyecto se centra en la aplicación de cinco metodologías de aprendizaje activo (Aprendizaje Basado en Problemas, Estudio de Casos, Aula Invertida (Just In Time Teaching y Team-Based Learning) y Aprendizaje-Servicio) en asignaturas teóricas y prácticas de titulaciones de grado y máster