MARIA JOSE AGUIRRE ARMELIN

MARIA JOSE AGUIRRE ARMELIN

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Aplicações da análise por ativação neutrônica para determinações multielementares em diferentes materiais
2022 - ARMELIN, MARIA J.A.
Neste trabalho é mostrado como INAA pode ser utilizada com sucesso para a solução de problemas analíticos que foram solicitados ao LAN (Laboratório de Análise por Ativação). Num primeiro caso, mostrou-se o desempenho da INAA como uma “técnica de referência”: 1) os valores das concentrações de As, Cd, Cr e Se, obtidos por INAA para fertilizantes minerais serviram como referência para checar os valores de concentrações obtidos pelo procedimento desenvolvido para determinar esses elementos por GF AAS e ICP OES nos mesmos fertilizantes; 2) os valores das concentrações de Au em carvão, obtidos por INAA serviram para avaliar a exatidão do procedimento de extrações em meio etanólico e alcalino do complexo Au(CN)3 do carvão ativado e posteriormente a determinação do Au por meio da espectrometria de absorção atômica de chama. Em outros casos, INAA foi aplicada para avaliar a eficiência de purificação da “Técnica de Refinamento Zonal” empregada para a purificação de cristais para serem utilizados como detectores de radiação X e gama e, também para avaliar a incorporação de nano partículas de Ag em cateter. Além do que mostrou ser uma opção para análise multielementar em matrizes orgânicas.
Multi-element contamination in soils from major mining areas in Northeastern of Brazil
2021 - MONTALVAN-OLIVARES, D.M.; SANTANA, C.S.; VELASCO, F.G.; LUZARDO, F.H.M.; ANDRADE, S.F.R.; TICIANELLI, R.B.; ARMELIN, M.J.A.; GENEZINI, F.A.
Mining has become one of the main factors in the global biogeochemical cycle of potentially toxic elements. Therefore, it is considered one of the anthropogenic activities with the greatest negative impact on the environment. These impacts are maximized in semiarid regions, where mining activities can lead to soil degradation and decrease in land productivity. This study aimed to assess the level of contamination in natural, urban, and agricultural soils of three important mining areas, where approximately 80,000 people live, and pollution levels have never been determined before. For this purpose, soil samples were collected around iron, uranium, and vanadium mines, as well as in the main human settlements of the region. The concentrations of 34 elements were determined by instrumental neutron analysis activation (INAA) and inductively coupled plasma optical emission spectrometry (ICP OES) techniques. Pollution indices (CF, EF, mCd, PLI, and REEP) revealed that there is a moderate to heavy level of pollution for 89% of the analyzed elements. Additionally, an extreme contamination level was observed in 78% of the samples, for at least one element. Statistical analyses were performed to identify patterns in the distribution and common sources of pollution. The results suggest that the concentrations for Al, Ba, Hf, Na, Pb, Rb, REE, Ta, Th, U, Zn, and Zr are associated with geogenic causes. However, the influence of anthropogenic sources such as agriculture and mining on the accumulation of these elements in soils should not be disregarded. In contrast, the contents of As, Br, Cd, Co, Cr, Cs, Cu, Fe, K, Mn, Ni, Sc, Ti, and V reflect the direct impact of anthropogenic sources.
Chia trace elements detection by neutron activation analysis
2020 - CHIERENTIN, GABRIEL de S.; ARMELIN, MARIA J.A.; MASTRO, NELIDA L. del
Chia seed is an ancient grain that is becoming popular in modern food regimen for their nutritional value and functional properties, although many tables of food composition do not provide complete information about it. Trace and ultra-trace elements are indispensable for human health as they are involved in biochemistry regulations, such as transport and oxygen activation, electron transport, catalytic center in oxide reduction processes, catalytic center in acid-base processes and structural function. For both diet assessment and prescription, reference values for trace elements as recommended daily intake, recommended dietary allowance and tolerable upper intake level were established. Instrumental neutron activation analysis (INAA) is a noble method to identify and quantify trace and ultra-trace elements that has high sensitivity for many elements, has little or no sample contamination, resulting in low blank values, has virtually no matrix effects and multi element capability. The aim of the present work was to identify and quantify by INAA mineral elements of chia seeds. The results showed higher content of Ca, K, Zn and Fe when compared with data from the literature obtained by other analytical methods. Besides that, using INAA was possible to detect elements that was not commonly verified with others measuring methods.
Impact of ionizing radiation on cake from Brazilian macadamia nut (Macadamia integrifolia) after oil extraction
2020 - RAO, INA P.; ARMELIN, MARIA J.A.; MASTRO, NELIDA L. del
Macadamia oil extraction is commonly performed by cold pressing. This process presents low extraction yields, generating partially defatted meal as a byproduct. To take advantage of their important nutritious components, we propose to use the cake after lipid extraction as a food ingredient following the elimination of potentially hazardous microbiological contamination. Food irradiation is a mature, effective, broad spectrum and residuefree technology that can play an important role in food safety and food security. This study presents the impact of gamma irradiation on the residual cake from Brazilian macadamia pressing. An absorbed dose of 5 kGy reduced yeasts, molds and aerobic mesophilic bacteria below admissible maxima. The concentration of important elements like Ca, Se, Mg or Mn appeared higher in the cake than in the nut itself as measured by instrumental neutron activation analysis (INAA).
Importance of the neutron activation analysis for the determination of elements in different organic materials
2019 - ARMELIN, MARIA J.A.; MOREIRA, EDSON G.
Instrumental Neutron Activation Analysis (INAA) was the analytical technique used to determine the concentrations of As, Ba, Br, Ca, Ce, Cl, Co, Cr, Fe, La, K, Mg, Mn, Pr, Sb, Sm, V and Zn in the following materials: petroleum, rubber, plastics and petroleum coke. The precision of the results were mostly between 1 and 20%. The technique is non-destructive and fast for Cl, Cu, Mg and V analyses. For this reason, INAA showed to be a good option to be applied in organic matrices.
Concentrations of Se, Ba, Zn and Mn in Brazil nuts
2019 - ARMELIN, M.J.A.; MAIHARA, V.A.; COZZOLINO, S.M.F.; SILVA, P.S.C.; SAIKI, M.
The concentrations of Se, Ba, Zn and Mn were determined in samples of Brazil nuts collected in two ways: a) in a production farm predominantly for export and, b) in various points of sale from different regions of Brazil. Instrumental neutron activation analysis was the analytical technique used in this study. Results indicate that the concentrations of Se and Ba varied greatly among the Brazil nut samples analyzed. This large variability may be related to the soil characteristics from which the nuts were produced. An inverse correlation was observed between the concentrations of Se and Ba. On the other hand, the concentrations of Zn and Mn did not show significant differences among these samples.
Performance of neutron activation analysis in the evaluation of bismuth iodide purification methodology
2017 - ARMELIN, M.J.A.; FERRAZ, C.M.; HAMADA, M.
Bismuth tri-iodide (BiI3) is an attractive material for using as a semiconductor. The behavior of semiconductor devices is strongly influenced by the presence of impurities or contaminants remaining due to incomplete purification of the semiconductor material. BiI3 has emerged as a particularly interesting material in view of its wide band gap (1.7eV), large density (5.7g/cm3), high atomic number elements (Z=68) and high resistivity (>109 cm). The BiI3 crystals have been grown by the vertical Bridgman technique using commercially available powder. In this case, the BiI3 powder was purified three times and, at each purification, the crystal was evaluated by systematic measurements of reduction of impurities, crystalline structure, stoichiometry and surface morphology. The purification efficiency was assessed by analyzing the crystals, through Instrumental Neutron Activation Analysis (INAA). INAA is the elemental analysis method usually chosen for these projects because of some features such as: small amount of sample available, minimal sample handling and high sensitivity for many elements. The analyzed crystals came from the impurity reduction process occurred after each purification by the Repeated Vertical Bridgman method. The results showed that INAA was a special analytical technique to identify and quantify the impurities (Ag, As, Br, Cr, K, Mo, Na and Sb) in the BiI3 crystals and to evaluate the reduction of the trace impurities, after each purification step.
Concentrations of Se, Ba, Zn and Mn in Brazil nuts
2017 - ARMELIN, MARIA J.A.; MAIHARA, VERA A.; COZOLLINO, SILVIA M.F.; CARDOSO, PAULO S.; SAIKI, MITIKO
The concentrations of Se, Ba, Zn and Mn were determined in samples of Brazil nuts collected in two ways: a) in a production farm predominantly for export and, b) in various points of sale from different regions of Brazil. Instrumental neutron activation analysis was the analytical technique used in this study. Results indicate that the concentrations of Se and Ba varied greatly among the Brazil nut samples analyzed. This large variability may be related to the soil characteristics from which the nuts were produced. An inverse correlation was observed between the concentrations of Se and Ba. On the other hand, the concentrations of Zn and Mn did not show significant differences among these samples.
Purification and crystal growth of the bismuth (III) iodide-influence of trace impurities on the crystal quality
2017 - FERRAZ, CAUE de M.; ARMELIN, MARIA J.A.; OLIVEIRA, RENE R.; OTUBO, LARISSA; MARTINS, JOAO F.T.; SANTOS, ROBINSON A. dos; COSTA, FABIO E.; CARVALHO, DIEGO V.S.; OMI, NELSON M.; MESQUITA, C.H.; HAMADA, MARGARIDA M.
This work describes the experimental procedure of purification and preparation of BiI3 crystals by Repeated Vertical Bridgman technique, aiming a future application of this semiconductor crystal as a room temperature radiation detector. The BiI3 powder used as raw material was purified three times and, at each purification, the crystal was evaluated by systematic measurements of the reduction of the impurities, crystalline structure, stoichiometry and surface morphology. The reduction of the trace metal impurities in the BiI3, at each purification, was analyzed by Instrumental Neutron Activation Analysis (INAA), in order to evaluate the efficiency of the purification technique established in this work. It was demonstrated that the Repeated Bridgman technique is effective to reduce the concentration of many impurities in BiI3, such as Ag, As, Br, Cr, K, Mo, Na and Sb. The crystalline structure of the BiI3 crystal purified twice and three times was similar to BiI3 pattern. However, for BiI3 powder and purified once, an intensity contribution of the BiOI was observed in the diffractograms. Improvement in the stoichiometric ratio was observed at each purification step, as well as the crystal surface morphology.
Activity levels of gamma-emitters in Brazil nuts
2016 - ARMELIN, M.J.A.; MAIHARA, V.A.; COZZOLINO, S.M.F.; SILVA, P.S.C.; SAIKI, M.
Activity concentrations of the radionuclides 137Cs, 40K, 226Ra and 228Ra were determined in Brazil nuts acquired at points of sale between 2010 and 2013. Results indicated that the estimated annual effective radioactive dose due to ingestion of Brazil nuts is 27% of the annual dose limit of 1 mSv y-1 for public exposure, according to the Interna-tional Commission on Radiological Protection (ICRP). To estimate this dose the highest activity concentration ob-tained for each radionuclide was considered, assuming an annual consumption of 1.5 kg y-1 per individual.