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  • Author or Editor: V. Maihara x
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Abstract  

The concentrations of Na, Cl, Mn, Br, Fe, Zn, Rb, Sb, Sc, Cr, Al and Mg were determined in some types of bread and in some brands of milk powder consumed in the city of São Paulo (SP—Brasil), by instrumental neutron activation analysis. Radiochemical separations were carried out by means of retention of24Na on hydrated antimony pentoxide (HAP) from a 8N HCl solution, after digestion of the organic matter. It was possible in this way to determine the radioisotopes64Cu,69mZn and140La in the effluent solution. The detection limits of the trace elements analyzed in bread and milk powder samples were determined using the Currie and Girardi criterions.

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Abstract  

Instrumental neutron activation analysis was applied to the determination of the elements Na, K, Br, As, Rb, Zn, Co, Fe and Sc in Brazilian rice samples and in biological standards. Hg and Se concentrations were determined by using a simple radiochemical separation. The chemical procedure was carried out by means of distillation of Hg and Se in HBr medium and subsequent precipitation of selenium by sodium metabisulfite and mercury by thioacetamide. The accuracy of the instrumental and radiochemical methods was evaluated by means of analysis of the Reference Materials NBS-Bovine Liver, Bowen's Kale and NBS-Rice Flour.

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Abstract  

A radiochemical separation procedure based on chromatographic separation using Chelex-100 in 0.1M HAc-0.1M NH4Ac at pH 4.8 and TDO in 6M HCl, has been developed to determine Cd, Co, Cr, Fe, Se, The, U, W and Zn in three biological materials of botanic origin used as SRM's: 1547 Peach Leaves, 1515 Apple Leaves and the new proposed material Spinach. The aim was to obtain more information for these elements whose values are not yet determined or are given only as suggested values.

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Abstract  

Instrumental neutron activation analysis (INAA) was applied to determine the elements Br, Ca, Cl, Cu, Fe, I, K, Mg, Mn, Na, Rb, S, V, Zn in five varieties of Brazilian corn, resulting from the studies carried out in order to increase their protein contents. The accuracy of the method was evaluated by means of reference material analysis. In general, the precision of the method was lower than 15%, except for Cu, I and S. Sensitivity and detection limit were also determined. Besides, tryptophan contents were determined. It was observed that the tryptophan content in improved corn samples was twice as large as in the normal samples. However, the same ratio was not observed in the inorganic element contents.

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Abstract  

Excess dietary intake may increase the risk for the hyperthyroidism in the elderly. This study investigated iodine dietary intake by epithermal neutron activation analysis (ENAA) analyzing duplicate portion diet and fortified table salt samples. Duplicate diet samples were obtained from a group of twenty-five steel mill workers from the city of São Paulo, over a 3-day period. The samples were freeze dried, mixed and homogenized. Fortified table salt brands were collected from the market and were analyzed with no pre-treatment. Assays for the iodine concentration in the table salt samples revealed values between 24 to 65 mg/kg. The average iodine daily intake for the worker’s diets was 813 μg/day, ranging from 402 to 1363 μg/day. In some cases daily intakes were around 10 times higher than the recommended dietary allowance (RDA) value (150 μg/day).

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Abstract  

Arsenic and cadmium contents in eight edible mushroom species (Agaricus bisporus, Agaricus sp, Pleurotus ostreatus, Pleorotus florida, Pleorotus eryngui, Pleurotus osteatus, Pleurotus salmoneostramineus, Lentinula edodes) consumed by Brazilian population were determined by instrumental neutron activation analysis (INAA) and graphite furnace atomic absorption spectrometry (GF AAS), respectively. Arsenic concentrations varied from 0.009 mg/kg in P. eryngui to 0.210 mg/kg dry weight in L. edodoes and Cd from 0.011 g/kg in P. eryngui to 0.229 mg/kg dw in P. salmoneostramineus. The consumption of mushrooms in São Paulo-Brazil may be considered safe from a toxicological point of view as As and Cd presented levels of ingestion are below the maximum levels recommended by the World Health Organization.

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Abstract  

Radiochemical procedures for the analysis of 210 Pb and 210 Po in foods and diets are presented. Because of the low beta energy of 210 Pb, its analysis was based on a separation of the daughter radionuclide 210 Bi by precipitation of lead sulphate, 210 Bi ingrowing and beta counting of this nuclide. 210 Po analysis was based on wet dissolution of the sample, deposition onto silver disc and counting by alpha-spectrometry. Levels of these radionuclides in individual items and diets of selected university students were determined in order to evaluate the intakes of 210 Pb and 210 Po as well as the dose due to ingestion of foods and diets in São Paulo city.

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Abstract  

The present paper describes radiochemical separation procedures developed for the determination of seven elements: As, Cd, Cr, Cu, Hg, Sb and Se in different Brazilian regional diets. In the case of the elements As, Hg, Sb and Se, the procedure was based on retention in inorganic exchanger TDO (tin dioxide) and determination of Hg by extraction with Ni(DDC)2. For determination of Cd, Cr, Cu and Se the procedure chosen was based on retention in inorganic exchanger HMD (hydrated managese dioxide) and extraction of Cu and Cd as diethyldithiocarbamate compounds. The accuracy and precision of the methods studied were tested by means of analyses of different reference materials. Due to the lack of data on trace element levels in Brazilian foodstuffs and diets, these methods were applied to determination of these elements in different Brazilian regional diets. These diets were supplied by the Food and Experimental Nutrition Department of the Faculty of Pharmaceutical Science, University of São Paulo. The daily dietary intake values for these diets are presented for As, Cd, Cr, Cu, Hg, Sb and Se.

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Abstract  

Instrumental neutron activation analysis (INAA) was used in the homogeneity study of a Perna perna (Linnaeus 1758) mussel reference material. Simultaneous determination of 15 elements in six bottles of the material, from a total of 171, was performed. The bottles were considered homogeneous for the analyzed elements, at the 95% confidence level, according to the analysis of variance test performed. Elements were also determined in one bottle with five different sample masses for minimum sample intake estimation. Results varied from 50 to 350 mg, depending on the element.

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Abstract  

Instrumental neutron activation analysis was used at a 2-month long isochronous short term stability test performed on a Perna perna mussel candidate reference material. The assessment of the analysis of variance test, as well as, the normalized results to the control temperature showed no systematic changes in the concentration of Ag, As, Br, Co, Cr, Cs, Fe, Eu, La, Na, Rb, Se, Sc, Th and Zn during the test period. The result showed that the candidate reference material may be transported under normal transport conditions without significant changes in composition for the determined elements.

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