Determination of some trace elements in some human concretions

The contents of Hg, Cr, La, Sc, Co, Fe and Sb in some human concretions have been determined by instrumental radioactivation analysis. Urinary bladder and kidney concretions surgical removed from the patient have also been analyzed.     

Determination of some trace elements in human tooth enamel

Determination of seven elements (Cu, Fe, Mg, Mn, Pb, Sr and Zn) in whole enamel and surface layers of extracted non-carious human teeth by FAAS, ETA AAS, ICP-AES and ICP-MS (Pb) is demonstrated. Techniques are described for obtaining whole enamel and its acid dissolution. Fifty microm width enamel layers from outer enamel surface to a 200 microm depth were successively etched in 1 mL of 3 M HClO4 for 3 min dissolution periods. Enamel samples were analyzed for populations under and over 20 years of age and enamel from Bronze Age teeth. Concentrations of microelements in the whole enamel and in the first surface layer (50 microm depth) were compared. With exception of Sr and Mg, all elements show significantly higher concentrations in the first layer than in whole enamel and higher concentration in teeth of individuals over 20 years, which demonstrate the cumulative effect of these elements. The Cu, Fe, Mn, Pb and Zn concentrations in four layers of erupted and non-erupted teeth decreased while Mg and Sr concentrations increased toward enamel-dentine junction. The concentrations of most elements were almost constant as they approached the 150 microm layer. This concentration gradient may result from interaction between saliva and teeth and supports the hypothesis that the surface de- and re-mineralization process is effective at most to 150 microm from the enamel surface.     

Determination of some trace elements in the thyroid gland by INAA

Neutron activation analysis without radiochemical separation was used for simultaneous analysis of eight trace elements in thyroid glands, obtained as necroptic material from persons not suffering from diseases of this gland. Inorganic standard solutions were used for calculations of concentrations of measured elements. Concentrations are expressed in ppm, or ppb. IAEA reference materials were used for quality assurance of analyses. From analyses of 42 thyroids concentration levels of Se, Cs, Sc, Fe, Cr, Zn, Co, and Rb and their variances in the thyroids were calculated. These results might serve as comparison material for medical research of pathological and functional changes in thyroid glands.     

Determination of some trace elements in different organs of normal rats

In our biological investigations some trace elements have been determined by instrumental radioactivation analysis in organs of normal rats. The results of trace element distribution of Cr, Zn, Br, Sb, Fe, Co, Sc, Ag and Na in liver, spleen, brain, lung, kidney and heart of normal rats are presented in the paper.     

Preconcentration of trace elements by aluminium hydroxide

Summary Coprecipitation of traces of cobalt, zinc, chromium, ruthenium and mercury with freshly precipitated aluminium hydroxide has been investigated by a radiotracer method. Investigations were performed over a wide range of pH. The results indicate that traces of cobalt, zinc and chromium could be almost completely coprecipitated between pH 6 and 10. On the other hand coprecipitation yield for ruthenium in this pH range do not exceed 95%, which is believed to be the consequence of the various physicochemical states of ruthenium. The coprecipitation yields for mercury are very low as a consequence of the presence of non-ionized HgCl₂.

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Zusammenfassung Die Mitfällung von Spuren Kobalt, Zink, Chrom, Ruthenium und Quecksilber mit frisch gefälltem Aluminiumhydroxid wurde radiochemisch untersucht. Die dazu nötigen Experimente erstreckten sich über ein weites pH-Gebiet. Die Ergebnisse zeigen, daß Spuren Kobalt, Zink und Chrom zwischen pH 6 und 10 fast vollständig mitgefällt werden konnten. Andrerseits sind die Mitfällungsausbeuten für Ruthenium in diesem pH-Gebiet nicht größer als 95%, was vermutlich die Folge der verschiedenen physikalischchemischen Zustände des Rutheniums ist. Die Mitfällungsausbeuten für Queckilber sind infolge der nur geringen Dissoziation des HgCl₂ sehr gering.

     

Determination of some toxic trace elements in Indian tobacco and its smoke

Toxic trace metals like mercury, arsenic and cadmium have been determined in widely used Indian chewing tobacco and cigarette tobacco by neutron activation followed by sequential radiochemical separation (RNAA). Differential Pulse Anodic Stripping Voltammetry (DPASV) has been used for the estimation of lead, cadmium and copper in cigarette tobacco and its smoke aerosols. The reliability of the data has been assured by analyzing standard reference materials, bovine liver (NBS-1577) and orchard leaves (NBS-1571), and intercomparison of the Pb, Cd and Cu values by three techniques, namely, RNAA, DPASV and Energy Dispersive X-ray Flourescence technique (EDXRF). The levels of Hg, Cd, As, Pb and Cu in cigarette and chewing tobacco and the estimated intake of Cd, Cu and Pb to the smoker are presented and discussed.     

Determination of some trace elements in high-purity aluminium, zinc and commercial steel by AAS after preconcentration on amberlite XAD-1180 resin

The determination of trace metals, e.g. Bi, Cd, Pb, in high-purity aluminium, zinc and commercial steel by flame or graphite furnace atomic absorption spectrometry following their preconcentrations as iodo complexes on XAD-1180 resin by means of a short column system is described. The recoveries are quantitative (95%). The relative standard deviations varies between 6% and 10%. The relative errors are less than 8% in a concentration range of 1 × 10^–3 –4 × 10^–5%. Detection limits for flame AAS and GFAAS were in the ranges of 0.002–0.110 g/ml and 0.0003–0.004 g/ml or in the ranges of 0.08–4.40 g/g and 0.012–0.16 g/g with respect to the solid samples, respectively.     

Determination of trace amounts of some elements in armco steel by the neutron activation method

The previously elaborated methods of the determination of As, Sc, La, Au, W, Mo, Ga and In have been adapted to the analysis of steel. Samples of Armco steel taken from three various points of a steel bar section were analysed. On the basis of the results obtained the distribution of the elements determined along the steel bar section is discussed.     

Determination of trace elements in some Nigerian vegetable based oils by neutron activation analysis

The concentrations of some essential micronutrient elements leadingto short-lived activation products in four Nigerian vegetable based oils (palmoil, palm kernel oil, sheabutter and groundnut oil) have been determined byneutron activation analysis using a small research reactor. One sample ofeach material was analysed and presented as an introduction for further investigations.Results indicate that the concentration range of the elements are 19.4–44.0µg/g for Al; 30.0–81.0 µg/g for Ca; 11.9–60.4 µg/gfor Cl; 1.43–5.96 µg/g for Cu; 7.3–28.1 µg/g for Mg;0.47–1.69 µg/g for Mn; 17.5–72.8 µg/g for Na and 0.04–0.07µg/g for V. The experimental procedure is suitable for routine determinationof micronutrient element in foods for control and monitoring purposes.     

Determination of trace elements in biological fluids

Main approaches to the trace element analysis of biological fluids and problems appearing in this case are considered. The specific character of these approaches is illustrated by the examples of the analysis of real samples for various trace elements. The advantage of methods for the direct determination of trace elements in these samples is demonstrated.     

Determination of some trace elements in natural and fertilised Libyan soils using INAA and ED-XRF

Samples of natural and fertilised soils were collected from Al-Gheran region, west of Tripoli, Libya. The samples were investigated by means of INAA and ED-XRF for Al, Si, K, Ca, Sc, Cr, Mn, Fe, Co, Zn, Br, Rb, Sr, Y, Zr, Nb, Cs, Ba, Hf, Ta, Pb and Th. The results indicate that the concentrations of K, Ca, Zn, Sr and Pb are 2–4 fold higher in fertilised compared to natural soil, while the concentrations of Al, Si, Cr, Mn, Fe, Co, Rb, Y, Nb, Cs, Ba Ta and Th are nearly the same in all samples. Mn and Fe values in two arable soils have been found to be 4–6 times lower than the average concentration in the earth's surface soils. This study concludes that, although the levels of some trace elements important for human health are very low in both natural and fertilised soils. Further research is needed to understand the full significance of the distribution transfer and toxicity of trace elements introduced in imported fertilisers.     

电感耦合等离子体发射光谱法测定铋黄铜合金中微量元素

利用ICP-AES(电感耦合等离子体发射光谱仪)研究了铋黄铜合金中铋、锑、铅、砷、铝、铁元素的测定方法,对仪器参数、分析谱线、干扰情况等因素进行了研究,确定了合适的谱线,并对铋黄铜合金进行精密度和回收实验。结果表明,相对标准偏差小于5%,回收率在94%～106%。     

Determination of light trace elements in surface layers

A method is presented for determining the concentration of light elements in a surface layer up to 15 μm deep, utilizing the anomalous increase in elastic scattering cross-sectional area when high-energy alpha-particles are scattered by light nuclei through large angles. For the separation of the short-lived nuclide¹⁷F, isotope-exchange between the solid and liquid phases was applied.     

Determination of protein-bound trace elements in bovine kidneys

Concentrations of up to 16 elements have been determined in subcellular fractions of bovine kidney using INAA methods. Levels of Rb and Se have been measured by a cyclic INAA method. A conventional INAA method consisting of 2 irradiations and 3 counting periods has been employed to determine the other elements. Accuracy of measurements has been evaluated by analyzing several standard reference materials. Trace element content of reagents used has been investigated in detail. Fresh samples of bovine kidney have been homogenized in a buffer containing sucrose and HEPES, and the homogeneate separated into nuclei, mitochondrial, lysosomal, microsomal and cytosol fractions by successive differential centrifugation. Concentrations of trace elements have been measured in these fractions using the INAA methods.     

A study of some trace elements in infant foods

Seven trace elements were determined in milk formulas, powder milk and infant food. Instrumental neutron activation analysis was used for the analysis of Fe, Zn, Co, Cr and Rb, while As and Cu content was determined using radiochemical neutron activation analysis. Differences were found in the trace element content of foods of the same type. Milk formulas are comparable with human milk according to the results obtained for the elements analyzed. The samples of powder cow's milk presented similar concentrations of the elements studied. Liver with vegetables was found to have the highest Cu content. A meal prepared at home, made of beef and fresh vegetables showed a higher trace element content than its similar commercial one. An estimation of the daily intake of the elements analyzed was made and compared with minimum recommended daily ingestion.     

Determination of trace elements in ambient aerosol samples

A microwave-assisted digestion procedure using HNO₃, HF, and H₂O₂ has been developed for analysis of elements in ambient particulate matter (PM). The samples are collected on cellulose filters and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The ICP-MS is calibrated with external standards, and recovery of analytes is tested with NIST SRM 1648 Urban Dust. This method has been used to quantify the airborne concentrations of a large number of elements, including Ag, As, Ba, Be, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, K, Li, Mg, Mn, Mo, Ni, Pb, Rb, Se, Sb, Sr, Ti, Tl, V, and Zn. For the majority of these elements, recovery of the NIST SRM is within 15% of the certified values.     

原油中微量金属元素的测定及风化条件下元素的变化规律

建立了微波消解-电感耦舍等离子体质谱(ICP.MS)法同时测定原油及自然风化后原油中的V、Cr、Mn、Fe、Ni、zn、Mo、Ba等11种微量金属元素的方法.结果表明,11种微量金属元素的检出限为0.0056～0.8729μg/g,线性关系良好,相关系数r≥0.9995;相对标准偏差(RSD)<5.0%.经过30d风化...     

Study of industrial electrowinning process of aluminium by INAA

A method is developed for measuring the current efficiency of an industrial aluminium electrowinning cell of the production plants of ALUMINA — Portovesme, in Sardinia. A mixed tracer (Au+Ag+Ir) was introduced into the cell, and samples of aluminium were periodically withdrawn and analyzed by INAA. The trend of aluminium production rate is studied before and after the casting. Data reliability and future developments are also discussed.