高温气冷堆球形燃料元件中基体石墨杂质含量的研究

研究了高温气冷堆球形燃料元件的基体石墨及所使用的主要原材料中微量及痕量杂质元素的含量，利用等离子发射光谱仪对Ｂ、Ｌｉ、Ｆｅ、Ｔｉ、Ｕ、Ｔｈ、Ｇｄ、Ｅｕ、Ｓｍ、Ｄｙ等十几种重要元素进行了分析，并比较了加工处理过程对于杂质离子含量的影响。研究结果表明，在球形燃料元件制造过程中所使用的原材料及制成的基体石墨均符合球形燃料元件的设计指标。     

Production of Nanoparticles in Thermal Plasmas: A Model Including Evaporation,Nucleation, Condensation,and Fractal Aggregation

In this work a coupled model for the production of nanoparticles in an inductively coupled plasma reactor is proposed. A Lagrangian approach is used to describe the evaporation of precursor particles and an Eulerian model accounting for particle nucleation, condensation, and fractal aggregation. The models of the precursor and nanoparticles are coupled with the magneto-hydrodynamic equations describing the plasma. The purpose of this study is to develop a model for the synthesis of particles in a thermal plasma reactor, which can be used to optimize industrial reactors. The growth of aggregates is considered by introducing a power law exponent D _f. Results are compared qualitatively and quantitatively with existing experimental data from plasma reactors at a relatively large laboratory scale. The results obtained from the model confirm the previously observed importance of the quench strategy in defining the morphology of the nanoparticles.     

Tea brewed in traditional metallic teapots as a significant source of lead,nickel and other chemical elements

An environmental inquiry conducted by the Brussels Inter-communal Laboratory of Chemistry and Bacteriology (BILCB) has revealed that in 2000?a traditional metallic teapot caused in Brussels lead intoxication among a family of Morocco origin. Following this case study of lead poisoning and subsequent preliminary results carried out by the BILCB, which confirmed the dangerousness of this kind of item, samples of traditional metallic teapots were collected from North African groceries in Brussels by the Institute of Public Health (IPH) in collaboration with the BILCB and the Federal Agency for the Safety of the Food Chain (FASFC). Aluminium, copper, iron, nickel, lead and zinc were analysed to identify metals with a potential to migrate into tea solutions. Simulants (natural tea, tea acidified with citric acid and citric acid) were brewed in those teapots in order to identify the leaching potential of migration at boiling point temperature for different contact periods. Multi-elementary analysis was carried out by inductively coupled plasma-atomic emission spectrometry (ICP-AES). It was concluded that the concentrations of those leached metals depend on the nature of the migration liquids, the type of teapots and the contact periods. Most teapots showed a high level of toxic metals in leachates for lead and to a less extent for nickel, which can contribute significantly to the risk of serious poisoning. A comparison of the results with the toxicological reference values was done. The teapots were withdrawn from the market by the FASFC.     

Proficiency test for the determination of heavy metals in mineral feed. The importance of correctly selecting the certified reference materials during method validation

In 2008, the International Measurement Evaluation Programme, IMEP®, organised two proficiency tests (PTs) for the determination of heavy metals in mineral feed, named IMEP-105 and IMEP-27, respectively. IMEP-105 was organised in support of the activities of the European Union Reference Laboratory for Heavy Metals in Feed and Food, and participation was restricted to the officially nominated National Reference Laboratories (NRLs). IMEP-27 was open to all interested control laboratories in the field. The test material used in the two PTs was the same and the timeframe of the two exercises overlapped. The measurands in both exercises were total Cd, Pb and As and extractable Cd and Pb, as defined in Directive 2002/32/EC of the European Parliament and the Council on undesirable substances in animal feed. Forty-nine laboratories from 25 countries reported results to the two exercises, 29 to IMEP-105 and 20 to IMEP-27. In both PTs, external reference values were used instead of consensus values derived from the participants' results. It was shown that the concentration of total and extractable Cd according to Directive 2002/32/EC were identical, while the concentration of extractable Pb was ～80% of total Pb. The main outcome of these comparisons was that an underestimation of the concentrations of the addressed measurands, in particular total Pb, took place due to an erroneous estimation of the bias of the analytical methods used by most of the participants. It appeared that the nature of the certified reference materials chosen for method validation and recovery estimation was the cause of the problem (insufficient matching of the matrix characteristics between these materials and the test sample). No significant difference between the results reported to IMEP-105 and to IMEP-27 was observed.     

Rapid sample preparation procedure for As speciation in food samples by LC-ICP-MS

This paper describes a rapid method for arsenic (As) speciation by LC-ICP-MS in several types of food samples. Prior to analysis, samples were milled and the As species extracted from biological tissues by sonication in only 2?min with a solution containing MeOH (10%, v/v) plus HNO₃ (2%, v/v). As species were separated by LC using an anion exchange column. Method detection limits for AsB, As³⁺, DMA, MMA and As⁵⁺ were 1.3, 0.9, 0.6, 0.7 and 0.8?ng?g^?1, respectively. Method accuracy and precision were traceable to Certified Reference Materials SRM1577 bovine liver from the National Institute of Standards and Technology, CE278 mussel tissue from the Institute of Reference Materials and Measurements and DOLT-3 dogfish liver tissue and DORM-3 fish protein from the National Research Council of Canada. Finally, the method was applied to speciate As in food samples (egg, fish muscle, beef and chicken) purchased in Brazilian markets.     

Modelling aluminium leaching into food from different foodware materials with multi-level factorial design of experiments

To estimate the contribution of aluminium (Al) leaching from different materials used for food preparation and serving to the dietary Al intake, Al release from foodware typically used in everyday life was investigated using multilevel factorial design (MFD) of experiments. For Al characterisation, sample preparation and an analytical method using inductively coupled plasma atomic emission spectroscopy was developed and validated. Parameter influence (temperature: x ₁, contact time: x ₂, pH: x ₃, salt concentration: x ₄, viscosity: x ₅), was evaluated with analysis of variance suggesting that the influence of viscosity is not significant compared to the other four studied parameters. Therefore, predictive, exponential quadratic regression models were established with x ₁–x ₄. Cross-validation and a set of independent experiments in real food products were used to test the prediction force of the different models. They both suggest that the quality of the models established for Al foil, Al plate and ceramic ware is satisfactory, but less good for glassware and stainless steel. Indeed, in the studied conditions, leaching from these latter food wares was often close to or even below the limit of quantification suggesting that the principal sources of Al intake from food contact materials during food processing are utensils made of Al and ceramic ware.     

ICP-AES法测定钢铁中锡

试验确定了用 ICP-AES法测定钢铁中锡最佳仪器工作参数 ,考察了基体及所用试剂对测定的影响。结果表明基体铁、硫酸对锡的测定均存在负干扰的问题 ,采用硝酸介质及与基体成分相匹配的方法 ,实现钢铁中锡的准确快速测定 ,方法检出限为 2 .1ng/m L,相对标准偏差小于 3 % (n=10 )。     

ICP-AES法测定生铁中微量元素

采用 ＩＣＰ－ＡＥＳ法测定生铁中Ｃｕ、Ｃｒ、Ａｓ、Ｍｏ、Ｖ、Ｗ、Ｓｂ、Ｚｎ、Ｎｉ、Ｓｎ １０种微量元素，提出对分析条件进行试验与探讨。实验结果表明。该法具有灵敏度高，准确度好，简便快速等优点。     

Determination of Sub-Trace Sc, Y and Ln in Carbonate by ICP-MS with Inter-Element Matrix-Matched Technique

Inductivelycoupledplasmamassspectrometry(ICP MS)isapowerfultechniquefortracemulti ele mentandisotopicanalysis[1,2 ] .Thistechniquecom binesthecharacteristicsoftheICPforatomizingandionizinginjectedmaterialwiththesensitivityofMS .Ithasbeensatisfactorilyappliedtotheanalysisofvari oussamplesinthefieldsofgeological,environmental ,industrial ,food ,medicalandnuclearsciences .How ever,highlevelsofmatrixelementcancausematrixeffectssuchasCa ,Mg ,K ,NaandCl .Severallitera tures[3～ 5] reportedthee…     

ICP-AES测定以硅酸盐为主的矿物中Al、Fe、Ca、Mg、K、Na、Ti、Mn等元素的方法

研究了应用电感耦合等离子体发射光谱法 ,选取适宜的仪器工作条件 ,分析硅酸盐矿样中Al、K、Na、Ca、Mg、Ti、Mn、Fe8个元素的方法。与传统方法相比 ,大大简化了操作程序和劳动强度 ,缩短了工作时间。用本法对岩石系列标准物质中 8个元素进行了分析 ,其结果与参值相符。