首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 38 毫秒
1.
Sixteen minor and trace element contents of diet samples from three different social population groups in Taiwan were determined. Samples were prepared using duplicate portion technique by collecting the 15 subjects ate and drank during a 3-day period. Samples were homogenized, freeze-dried, and elemental concentration of minor and trace elements were determined by instrumental neutron activation analysis. Elemental concentrations and daily dietary intake of the elements were compared with those in the other nations, and possible origins were discussed.  相似文献   

2.
川稻中铜铁锌锰四种微量元素的研究   总被引:13,自引:0,他引:13  
四川是我国农业大省之一,水稻居其粮食作物的首位。而微量元素对生命有着重要的意义。本文对四川省稻米中铜、铁、锌、锰四种微量元素进行了分析研究,探索了它们大致的含量范围和糙米、精米及谷壳中微量元素含量的差异,证实了稻谷产量与以上四种微量元素总量间以及大米品质与铜、锌含量间呈正相关关系,也表明了大米中微量元素含量与土壤环境的正相关性。  相似文献   

3.
Major, minor and trace element mass fractions were determined using wavelength dispersive and energy dispersive X-ray fluorescence and instrumental neutron activation analysis for five clay certified reference materials (NCS DC 60102–60105, 61101) distributed by the National Research Center for Certified Reference Materials in China. We report mass fractions for 10 major and the following 29 minor and trace elements: As, Ba, Ce, Co, Cr, Cs, Cu, Eu, Hf, La, Lu, Nb, Nd, Ni, Pb, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, U, V, Y, Yb, Zn, and Zr.  相似文献   

4.
In human nutrition research, nuclear analytical techniques, particularly neutron activation analysis (NAA), are used mainly for thein vitro study of trace elements. According to work sponsored by the IAEA, up to 15 trace elements and 5 minor elements of nutritional interest may be determined in biological materials by NAA with good accuracy and precision. A programme is described in which NAA was used for the determination of 14 trace elements and one minor element in human milk. NAA also plays an important role in the certification of reference materials for nutritional studies.  相似文献   

5.
Summary Forty-five sherds of Roman terra sigillata were analysed for seven major and minor elements by inductively coupled plasma emission spectroscopy and for thirty trace elements by instrumental neutron activation analysis. Autoscaling, cluster analysis and principal component analysis were performed on the analytical data to obtain separate classifications of the sherds by accounting for major and minor elements, on the one side, and for trace elements, on the other. The ability of each element in discriminating between the obtained groups was determined by accounting for either Fisher weights or mutual correlations. The results obtained indicated that some major and minor elements display a greater discriminating capability than trace elements, and that the latter allow recognition of a greater number of compositional groups just because they greatly outnumber major and minor elements.  相似文献   

6.
Traces of Mn(II), Co(II), and Ni(II) and minor amounts (up to 20 mg of these elements are separated from gram amounts of tellurium by cation-exchange chromatography on small columns (3 g) of macroporous AG MP-50 resin or larger colunns (5 g) of microporous AG 50W-X8 resin. The trace elements are retained from 0.5 M HCl containing 70% acetone while tellurium passes through and is eluted completely with this solution. The trace elements are then eluted with 3.0 M HCl and can be determined by atomic absorption spectrometry. Copper (II) can also be separated but requires a 10-g column of AG MP-50 resin. Separations are sharp and quantitative and only microgram amounts of tellurium remain in the trace element fraction when a 3-g sample of tellurium dioxide is taken; 10-μg amounts of the trace elements were separated from such samples and determined with standard deviations of <1%. Relevant elution curves and results for the analysis of synthetic mixtures are presented.  相似文献   

7.
为使人们更好地控制和调节硒的摄入量,用紫外分光光度法测定了大米中的硒含量。样品通过混酸消化,将有机硒转化成无机硒,酸性条件下,Se(Ⅳ)与邻苯二胺反应,产物在335nm有最大吸收峰。测定结果表明,天津小站米、东北米、丝苗米、泰国香米、富硒米的有机硒含量分别为:0.041、0.046、0.035、0.034、2.021μg/g,有机硒含量占总硒含量的比例分别是89.13%、82.14%、87.50%、80.95%、98.92%。富硒米硒含量及有机硒的比例明显高于其它种类的米。  相似文献   

8.
Rice grain samples and surface paddy soil samples were collected from 20 sites throughout Aomori Prefecture, Japan, and the concentrations of 25 elements in the polished rice and 33 elements in the soils were determined by neutron activation analysis, inductively coupled plasma-mass spectrometer or atomic adsorption spectrometer. The range of essential element concentrations in the polished rice was within one order of magnitude, however, the range for most of the trace elements was more than one order of magnitude. The range of element concentrations, except for I, in the paddy soils was within one order of magnitude. The ±95% confidence intervals of the soil-to-polished rice transfer factors for all elements, except for Pb, were within two orders of magnitude, and the geometric mean values were as follows: Cl, Mo and Zn (0.1–1); K, Cu, Cd, Rb, Mg, Mn, and Ag (0.01–0.1); Ni, As, Ca, Se and I (0.001–0.01); Na, Cs, Sr, Co, Cr, V, Ba, Pb, Fe and Al (<0.001).  相似文献   

9.
The minor and trace element content in coal is of great interest due to the potential impact on the environment from the release of these elements during combustion. Reducing the concentrations of potentially hazardous elements in coal prior to combustion is one way of dealing with this issue. In this research particle induced X-ray emission (PIXE) was used to investigate a hydrothermal leaching process for the removal of trace elements from a bituminous coal. The leaching agents HNO3 and NaOH were evaluated along with the effects of process parameters (temperature, pressure, and time) on the method's effectiveness. The variable with the greatest influence was the leaching agent itself. HNO3 was determined to be more effective than NaOH in reducing elemental concentrations for nearly all the elements determined. Increasing the temperature did result in greater reductions for some elements (Cl, Br, Zn) whereas increasing the pressure and duration of the leaching process had minimal impact on reductions, in elemental concentrations.  相似文献   

10.
Ivanova E  Havezov I 《Talanta》1995,42(9):1259-1263
A flame AAS method is used for the determination of dopants and impurities in potassium titanylphosphate (KTP) single crystals. Sample digestion using sulphuric acid and hydrofluoric acid is proposed as being the most appropriate procedure. The effect of major and minor components in the sample solution on the analytical signal is studied. The content of the dopants Cr, Mn and Ni (at a level of about 1 mg g(-1)) as well as the content of the impurities Fe, Na, Mg, W and Al (from 4 mug g(-1), depending on the trace metal) in the KTP single crystals is determined. The precision of the method is characterized by a relative standard deviation of 3-10%. The accuracy is checked by comparison with ICP-AES data for the trace element content in the KTP single crystals.  相似文献   

11.
Summary Capillary electrophoretic methods were developed to investigate the possibility of prolamin identification of four rice varieties i.e. Thai white fragrant rice KD105, Korkhor15, Thai white rice A, and a Chinese white rice H20. Two extraction methods were compared and varietal identification of rice prolamins was successfully accomplished by capillary electrophoresis in pH 2.5, sodium phosphate buffer containing 20% acetonitrile and 0.05% hydroxypropylmethylcellulose.  相似文献   

12.
In this work k0-INAA (via IAEAk0-software) has been applied on glass samples to determine major, minor and trace element concentration. As many as 50 elements were detected and quantified with 3–5 mg of 0.1 % AuAl comparator monitor (0.1 % gold–99.9 %Alumimum wire). The average concentration of SiO2, Na2O, CaO, Al2O3 and MgO ranged between 76–96 %, 11.15–12.66 %, 5.26–10.71 %, 1.13–2.73 % and 3.51–6.23 % respectively. The relative concentrations of impurity elements; Cr, Fe, Mn and Co determined from the glass samples were used to match the physical appearance (color) of the glass based on general knowledge of colored glass production. The analytical procedure was validated using SRM 610 (glass matrix) and SRM GBW07106 (rock matrix) both as control samples which indicated a relative uncertainty of 15 and 6 % respectively for SRM 610 and SRM GBW07106. The relative sensitivity at which some of the elements were detected in major, minor and trace levels have indicated, that the k0-method in instrumental neutron activation analysis using low power research reactor is a useful technique in glass analysis and could equally be used for forensic and archeological glass characterization.  相似文献   

13.
为探讨孕妇体内微量元素与妊娠并发症的关系,采用回顾性分析的方法,分析了住院分娩有妊娠并发症的孕妇体内微量元素的变化,其中妊高征、胎膜早破、胎儿宫内窘迫、FGR各5 0例,并随机选取同期住院分娩无任何合并症和并发症的孕妇5 0例作为对照组,测定其体内微量元素Zn、Fe、Cu的代谢情况,并探讨其相关性。结果表明,妊高征、胎膜早破、FGR、胎儿宫内窘迫孕妇的静脉血中Zn含量明显低于正常孕妇组,胎膜早破的孕妇血中Cu含量明显低于正常孕妇组(P <0 0 1 ) ,FGR、胎儿宫内窘迫的孕妇血中含Fe量也明显偏低,与正常孕妇组比较,差异有显著性意义。结论是妊娠并发症的出现与孕妇血中的微量元素代谢异常可能有一定的关系  相似文献   

14.
Clinoptilolite, a type of natural zeolite, has been commonly used as pozzolanic additive in concrete. This type of natural zeolite is generally used as a mineral admixture by substitution in Portland cement to produce high performance concretes. In the present study, the major, minor and trace element levels present in the clinoptilolite-rich natural zeolite (CRNZ) have been determined using a wavelength dispersive X-ray fluorescence spectrometer. Also, the clinoptilolite-rich natural zeolite has been compared with Portland cement with respect to the radiation attenuation properties. From the results it can be concluded that due to the natural radioactive content of clinoptilolite-rich natural zeolite (CRNZ) even if it is in trace level and also due to the poorer X-ray attenuation compared with Portland cement, special care should be taken to use this type of natural zeolite as blend materials in cements, etc.  相似文献   

15.
The use of trace element analysis in the forensic examination of fibres has been investigated. Samples of both natural and synthetic fibres have been analysed to show that it is possible to both identify and discriminate between samples that would, by present methods, be considered indistinguishable. A number of wool garments of predetermined trace element composition were sent for wear for a period of nine months. The conditions and frequency of wear and cleaning were reported to enable their effect upon the trace element composition of these garments to be determined. The wool samples were analysed by both short (30 min) and long (50 hrs) irradiations in a reactor flux of about 1012 n·cm−2·sec−1. This permitted the concentrations of the elements such as sodium, chlorine, iodine, manganese, cobalt and chromium to be determined. Both sodium iodide and lithium drifted germanium detectors were used to measure the induced activity of the wool samples. The composition of a range of acrylic fibres from a variety of sources has also been examined using a sodium iodide detector. The concentrations of sodium chlorine, bromine, managese, copper, aluminium, titanium, indium and barium were determined in these samples.  相似文献   

16.
《Analytical letters》2012,45(5-6):603-612
In the present study the possibilities of electrothermal vaporization inductively coupled plasma optical emission spectrometry (ETV-ICP-OES) for characterization of archaeological glasses were investigated. The objects of our research were fragments of a colorless late antique Roman flat window glass (fifth century A.D.) and colored medieval glass bracelets (eleventh–twelfth century A.D.) excavated in the region of Pernik (West Bulgaria).

The finely ground glass samples were analyzed directly and CHF3 was used as evaporation and transport modifier. Dried aqueous standard solutions and certified reference materials with different matrix (glass, fly ash, and stream sediment) were used as calibration standards. No matrix effects were observed by the optimized conditions. Measurements were performed using common calibration curves obtained with all appropriate calibration standards and major, minor, and trace element concentrations were determined. ETV-ICP-OES analytical data were used to establish the type of glass, the fluxing agents, the typical coloring and decoloring elements, and the recipe norm.  相似文献   

17.
In the study of trace elements in the different human brain areas, a critical evaluation of the values available in the literature is of great importance in attempting to establish reliable baseline levels, i.e., Reference Values (RVs) for toxicological assessment studies.This paper reviews the published values of minor and trace elements in the pituitary gland (hypophysis) of “normal” humans.Eighteen published papers are taken into account, 15 of which refer to the entire gland, whereas in three of them, only the adenohypophysis is considered.It turns out that essential elements such as Cu, Fe, Se and Zn were more frequently determined, whereas As, Br, Ca, Co, Cr, Cs, K, Mg, Mn, Ni and Rb were seldom investigated.Mercury was determined by several authors because of the concern caused by Hg release from dental amalgam fillings.Most values were obtained by Neutron Activation Analysis (NAA), which appears to have played a pioneer role in this field.Literature data on trace element levels in pituitary gland are at present insufficient to establish RVs; rather, they can be considered only as indicative values.Future investigations based on large populations of control subjects, with standardization of the preanalytical factors and the use of fit-for-purpose Standard or Certified Reference Materials (SRMs, CRMs) should therefore be envisaged.  相似文献   

18.
Laser ablation inductive coupled plasma – mass spectrometry (LA-ICP-MS) was used to analyse minor and trace elements in the hard parts of a shellfish, representing the environmental changes. A large, long-lived bivalve such as Arctica islandica can produce historical records of trace element fluctuations in seawater. Analytical traverses using LA-ICP-MS were performed from the inner to the outer wall of the shell at different locations. The development of the UV laser system now offers spatial resolution of craters of 10 μm diameter, enabling several analyses between the various growthbands. The elemental changes between growthbands of the shell are discussed, showing the potential for precise determination of heavy-metal pollution over the years.  相似文献   

19.
Silicon is an essential trace element and is found in vegetables, fruits, cereals, water, pasta and rice (Oryza sativa). In this work, the silica content of different types of rice grains were measured. Here, we used the heteropoly blue photometric method with a double beam UV-vis spectrophotometer to determine the amount of silicon in rice samples (n = 7) that were collected in the north of Iran. The samples were digested with wet-ashing method by microwave-assisted heating and then treated with ammonium molybdate to produce a yellow color compound in acidic solution (ca. pH 1.2) and then reduced to give a heteropoly compound with a blue color. Analyses were performed using standard addition method and absorbance values were measured with double beam UV-vis spectrophotometer at λmax = 815 nm. Results indicated that the silica content was 307-451 mg/kg for the samples. X-ray diffraction patterns and infra-red spectra were obtained from rice samples without any sample treatment.  相似文献   

20.
Summary Trace elements were determined in 27 brands of nail polish using INAA so as to estimate the impact of nail polish remainders when using (finger, toe) nail clippings as a bioindicator for epidemiological studies. Fe was found to be present up to almost 1.7% in one brand. No unambiguous correlation between trace elements and color was established, though transparent polish has the lowest trace element concentrations. An estimate of the maximum effect (no removal of the paint) indicates that over-estimates of some trace element levels in nail with more than 200.000% may occur. This study showed that if nail clippings will be used to study trace elements, very high demands have to be set to the efficiency and selectivity of the cleaning procedure.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号