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  • Author or Editor: A. Chatt x
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Abstract  

It is known that in the Turkish soil Se and Zn concentrations are somewhatlower than in other countries. Lower zinc intake causes significant healthproblems mostly at rural areas. Six different population groups, total of55 subjects, consisting of children, people from rural areas, university studentsand staff members were selected and diet samples were collected by duplicateportion technique. Bread and flour samples were collected from six differentbakeries in Ankara. Zinc, selenium and other trace elements in these sampleswere analyzed mostly by INAA. Daily dietary zinc intake differs among differentgroups, ranging 5–13 mg Zn/day, and for all cases, it is lower thanRDA value of 15 mg Zn/day. Similarly, selenium daily intake is around 20–53µg Se/day, which is also lower than RDA value of 55–70 µgSe/day.

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Abstract  

A pseudo-cyclic instrumental neutron activation analysis method in conjunction with anti-coincidence gamma-ray spectrometry (PC-INAA-AC) has been developed for the determination of ppb levels of Se. The method consists of repetitions of the irradiation-decay-counting cycles of a sample using the rapid transfer cyclic system at the Dalhousie University SLOWPOKE-2 reactor facility. The 162-keV γ-ray of 77mSe (t 1/2 = 17.4 s) has been found to be highly selective. The precision and detection limits are significantly improved and the total experimental time drastically reduced by this method. Detection limits are between 2 and 9 ng. The accuracy of the method has been evaluated by analyzing a number of nutritional reference materials. The PC-INAA-AC method has been applied for the routine determination of Se to the composites of 135 food samples with values ranging from as low as 1 ng g−1 for tea to 1,045 ng g−1 for organ meats on fresh weight basis.

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Abstract  

An epi-thermal instrumental neutron activation analysis (EINAA) method in conjunction with Compton suppression spectrometry (EINAA-CSS) was used for the determination of total iodine in eight different species of edible seaweeds from Japan. This method gave an absolute detection limit of about 2 μg. The accuracy of the method was evaluated using various reference materials and found to be generally in agreement within ±6% of the certified values. The longitudinal distributions of iodine at different growing stages in Japanese sea mustard and tangle seaweeds were investigated. For a 150-cm-high tangle, the highest concentration (5,360 mg/kg) of iodine was found at the root, then decreased slowly to 780 mg/kg in the middle portion (60–75 cm), and increased to 2,300 mg/kg at the apex. On the other hand, for a 190-cm-high sea mustard the highest levels of iodine were found both at the roots (164 mg/kg) and apex (152 mg/kg) with lower values (98 mg/kg) in the middle section. In order to estimate the bioaccessible fraction of iodine, seaweeds were digested by an in vitro enzymolysis method, dietary fibre separated from residue, and both fractions analyzed by EINAA-CSS. The average daily dietary intakes of total (0.14 mg) as well as bioaccessible fraction (0.12 mg) of iodine from the consumption of sea mustards were estimated.

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Abstract  

The extraction behavior of Sm(III), Eu(III) and Dy(III) with 1-nitroso-2-naphthol (HA) and trioctylphosphine oxide (TOPO) in methyl isobutyl ketone (MIBK) from aqueous NaClO4 solutions in the pH range 4–9 at 0.1M ionic strength has been studied. The equilibrium concentrations of Sm and Dy were measured using their short-lived neutron activation products,155Sm and165mDy, respectively. In the case of Eu, the concentrations were assayed through the152,154Eu radiotracer. The distribution ratios of these elements were determined as a function of pH, 1-nitroso-2-naphthol and TOPO concentrations. The extractions of Sm, Eu and Dy were found to be quantitative with MIBK solutions in the pH range 5.9–7.5, 5.6–7.5 and 5.8–7.5, respectively. Quantitative extraction of Eu was also obtained between pH 5.8 and 8.8 with chloroform solutions. The results show that these lanthanides (Ln) are extracted as LnA3 chelates with 1-nitroso-2-naphthol alone, and in the presence of TOPO as LnA3(TOPO) and LnA3(TOPO)2 adducts. The extraction constants and the adduct formation constants of these complexes have been calculated.

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Abstract  

The neutron spectra of one outer (#10) and two inner (#2 and #3) sites of the Dalhousie University SLOWPOKE-2 reactor (DUSR) have been calibrated for the k 0-based neutron activation analysis (k 0-NAA). The parameters determined include the cadmium ratio (R Cd), epithermal neutron flux shape factor (), subcadmium-to-epithermal neutron flux ratio (f), thermal-to-fast neutron flux ratio (f F), modified spectral index r()(Tn/T0)1/2, Westcott g Lu(T n)-factor, and absolute neutron temperature (T n). The a-values of -0.0098±0.0045 and -0.0425±0.0047 and -0.0422±0.0053 and f-values of 57.1±2.2 and 18.8±0.4 and 18.9±0.4 were obtained for the sites #10, #2 and #3, respectively. The modified spectral index (MSI), g Lu(T n)-factor, and T n have been determined for the handling of non 1/v (n,) reactions. The accuracy of the method was evaluated by analyzing reference materials.

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Abstract  

We have collected sixteen total diet samples from two socioeconomic groups in Turkey by duplicate portion techniques. Samples were homogenized with titanium-blade homogenizer, freeze dried and analyzed for their minor and trace elements mostly by neutron activation analysis. Bread and flour samples were also collected from the same regions and analyzed similarly by instrumental neutron activation analysis. We have determined concentrations of more than 25 elements in total diets, bread and flour, and fiber and phytate in total diets. We have determined daily dietary intakes of these population groups, probable source of elements through correlation coefficients, and enrichment factor calculations.

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