Standard Reference Materials (SRMs) for the Calibration and Validation of Analytical Methods for PCBs (as Aroclor Mixtures)

Six Standard Reference Materials (SRMs®) have been prepared by the National Institute of Standards and Technology (NIST) for the determination of PCBs as different Aroclor mixtures in methanol. Six additional SRMs of the same Aroclors in transformer oil have also been prepared. Specifically, solutions of Aroclors 1016, 1232, 1242, 1254, and 1260 have been gravimetrically prepared (individually) in methanol and transformer oil, mixed, and transferred to amber glass ampoules in approximately 1.2 mL aliquots. Gas chromatography with electron capture detection (GC-ECD) has been used to verify the gravimetric data for each solution and transformer oil SRM. Liquid chromatography was used for the isolation of the Aroclors from the transformer oil SRMs prior to GC-ECD analysis. Separate calibration solutions and oils were prepared with Aroclor levels similar to those in each methanol solution and transformer oil SRM and were processed alongside the samples. The GC-ECD response of each Aroclor was monitored relative to internal standards that were added to the complex mixtures for quantification. The gravimetric concentrations of Aroclors 1242 and 1254 in methanol were also examined by the same method of analysis (GC-ECD) using several different sources of Aroclors and two different capillary GC columns: a 5 % phenyl methylpolysiloxane phase and a relatively non-polar phase. The preparation of the materials, the gas chromatographic results, and the certified concentration values for each Aroclor SRM are described in this paper.     

变压器油的红外光谱分析

用红外光谱法对进口变压器油及其油泥进行定性分析。实验结果表明,进口变压器油与原桶新油比较,其化学成份已发生明显变化。     

3-硝基-1,2,4-三唑-5-酮标准物质的制备

介绍了3-硝基-1,2,4-三唑-5-酮(NTO)标准物质的制备方法。以工业品NTO为基体,经热过滤除去机械杂质、重结晶、低沸点溶剂煮洗、真空干燥等步骤,制备出均匀、稳定的NTO标准物质。使用液相色谱测试主体成分含量,对制备的标准物质进行了均匀性初检,并进行均匀性、稳定性评价研究。研究结果表明,NTO标准物质纯度达到99.91%,均匀性良好,稳定性在一年以上,达到了标准物质的技术指标要求。     

巨型变压器钳夹式油箱试验模态分析

本文对巨型变压器钳夹式油箱结构进行了试验模态分析,并用模态试验得到的精确模态参数,检验和修正了油箱结构的动态分析数学模型.文中介绍了油箱结构模态试验方法和试验设备及有限元动态分析数学模型的修正,还对结果进行了分析和讨论.     

高效液相色谱法测定绝缘油中糠醛含量的不确定度评定

绝缘油中的糠醛含量能够评估变压器绝缘纸的老化状况,并反映其绝缘性能.通过高效液相色谱法对绝缘油中糠醛含量进行定量分析,建立数学模型,确定测定结果的不确定度来源为糠醛标准物质、标准油液的配制、标准曲线的拟合、样品制备、回收率、测量重复性,并对测试结果进行不确定度评定.实验结果表明,绝缘油中糠醛样品浓度为1.05 mg/k...     

血液粘性测量标准物质前期研究

探讨了聚乙二醇6000作为血液粘性测量标准物质的可行性。依据国际血液学标准化委员会2009年发布的血液流变学实验室技术的指导意见,分析了作为血液粘性测量标准物质的必要条件,选用高纯度的聚乙二醇6000配制了2种不同浓度的水溶液作为此标准物质的候选物,并使用英国马尔文仪器公司Gemini HR nano200高精密度高级旋转流变仪对这2种水溶液流变性进行了均匀性、稳定性检验。定值研究与不确定度评定的结果为:1号溶液(3.95±0.18 )mPa·s,2号溶液(10.03±0.56 )mPa·s,表明该物质可以满足血液粘性测量的质量控制需要,可作为标准物质候选物。     

Selection of Applications for a Material

Finding an application for a given (not necessarily new) material is an elusive problem. Methods for material selection to fill a given application are now well developed. But the inverse problem – that of finding applications for a new material – has no such established methodology. The article discusses some general approaches to the problem and demonstrates recent progress in implementing them.     

氮中乙烷气体标准物质的研制

本文介绍了氮中乙烷气体标准物质制备的原理和过程,运用气相色谱仪对该气体标准物质进行比较法定值,同时对研制气体标准物质的压力变化均匀性以及储存时间稳定性考察,以及对引入的不确定度进行计算评估.试验结果表明研制的气体标准物质量值准确可靠,在浓度范围内具备良好的均匀性和稳定性,技术指标达到了项目预期目标.     

动物检疫领域标准样品的研制方法

动物源性食品安全问题是现今最重大的公共卫生问题(例如:禽流感、口蹄疫、甲型H1N1型流感等),而动物源性疾病的准确检测又成为保证我国食品安全中最突出的问题.本文介绍了动物检疫领域标准样品的国内外研制现状、研究内容、技术路线及应用推广前景等,为动物检疫标准样品的研制工作提供了借鉴.     

氩中氖气体标准物质的制备

论述了氩中氖气体标准物质的制备方法、稳定性参考值、不确定度计算,证明达到国家二级气体标准物质要求.该制备方法可行,量值准确可靠.     

氢中氮气体标准物质的研制

叙述了用于仪器仪表校正和产品质量检测使用的氢中氮气体标准样品的制备,以气相色谱法对其各项性能进行考核,确保其数据准确可靠。     

汽车尾气检测用气体标准样品的研制

叙述了轻型汽车污染物检测仪器使用的氮气中一氧化碳、二氧化碳、丙烷、一氧化氮气体标准样品的制备,以气相色谱法对其均匀性和稳定性进行考核,确保检测数据准确可靠。配制的标准气体的浓度为（10～500）×10^-6（mol／mol）。     

多维元素片中维生素B1基体标准物质的研制

建立了多维元素片中维生素B1基体标准物质的定值方法。以酸水解与离心的方法处理样品,使用高准确性的同位素稀释质谱法与高效液相色谱法2种分析方法定值。选用美国国家标准技术研究院SRM 3280多维元素片标准物质对方法进行了确认;同时该标准物质经过2个实验室的试用,进一步验证了其定值的准确性。研制的多维元素片中维生素B1的标准值为2.76mg/g,扩展不确定度为0.22mg/g(k=2)。     

采用比较法研制二级气体标准物质

以氮中二氧化碳二级气体标准物质的研制为例,探讨采用比较法研制二级气体标准物质及其不确定度的分析计算,其中标准物质的制备采用称量法配制,并对所研制的样品进行了均匀性、稳定性试验,结果表明,所研制的氮中二氧化碳气体的标准物质在一年的考察期内,其均匀性、稳定性、量值不确定度均达到国家二级标准物质要求,符合申报条件。     

氮中乙烯气体标准物质的制备

论述了氮中乙烯气体标准物质的制备方法、稳定性参考值、不确定度计算,证明达到国家二级气体标准物质要求。制备方法可行,量值准确可靠。     

Determination of Trace Level Iodine in Biological and Botanical Reference Materials by Isotope Dilution Mass Spectrometry

A method has been developed for the determination of trace level iodine in biological and botanical materials. The method consists of spiking a sample with ¹²⁹I, equilibration of the spike with the natural iodine, wet ashing under carefully controlled conditions, and separation of the iodine by co-precipitation with silver chloride. Measurement of the ¹²⁹I/¹²⁷I ratio is accomplished by negative thermal ionization mass spectrometry using LaB₆ for ionization enhancement. The application of the method to the certification of trace iodine in two Standard Reference Materials is described.     

Copper Oxide Precipitates in NBS Standard Reference Material 482

Copper oxide has been detected in the copper containing alloys of NBS Standard Reference Material (SRM) 482. This occurrence is significant because it represents heterogeneity within a standard reference material that was certified to be homogeneous on a micrometer scale. Oxide occurs as elliptically to spherically shaped precipitates whose size differs with alloy composition. The largest precipitates occur in the Au20-Cu80 alloy and range in size from submicrometer up to 2 μm in diameter. Precipitates are observed using light microscopy, electron microscopy, and secondary ion mass spectrometry (SIMS). SIMS has demonstrated that the precipitates are present within all the SRM 482 wires that contain copper. Only the pure gold wire is precipitate free. Initial results from the analysis of the Au20-Cu80 alloy indicate that the percentage of precipitates is less than 1 % by area. Electron probe microanalysis (EPMA) of large (2 μm) precipitates in this same alloy indicates that precipitates are detectable by EPMA and that their composition differs significantly from the certified alloy composition. The small size and low percentage of these oxide precipitates minimizes the impact that they have upon the intended use of this standard for electron probe microanalysis. Heterogeneity caused by these oxide precipitates may however preclude the use of this standard for automated EPMA analyses and other microanalysis techniques.     

大肠杆菌定量检测用标准物质的研制

采用平板计数法考察复合保护剂对大肠杆菌标准物质冻干粉的保护效率以及均匀性、稳定性。结果显示:复合保护剂对大肠杆菌保护率达到53.19%,可以在冻干过程中有效保护菌体。将大肠杆菌与冻干保护剂混合后,经冷冻干燥制备成干粉状标准物质,形态好、复水速度快、均匀性良好,可以稳定保存半年。该标准物质可用于食品检测实验室质量控制和食品中大肠杆菌检测结果的评价。     

六氟化硫中六氟乙烷气体标准物质的研制

采用称量法制备并计算定值,研制(10~100)×10-6(mol/mol)六氟化硫中六氟乙烷气体标准物质。采用自主研制的钢瓶自动清洗系统、配气系统和优化的配气工艺流程保证了研制水平。对气体标准物质进行了制备方法的研究、均匀性与稳定性检验试验,结果表明研制的气体标准物质定值的扩展不确定度优于1.5%(k=2),符合气体标准物质制备要求。     

Preparation and Comprehensive Characterization of a Calcium Hydroxyapatite Reference Material

Numerous biological and chemical studies involve the use of calcium hydroxyapatite (HA), Ca₁₀(PO₄)₆(OH)₂. In this study detailed physicochemical characterization of HA, prepared from an aqueous solution, was carried out employing different methods and techniques: chemical and thermal analyses, x-ray diffraction, infrared and Raman spectroscopies, scanning and transmission microscopies, and Brunauer, Emmett, and Teller (BET) surface-area method. The contents of calcium (Ca²⁺), phosphate (PO₄³⁻), hydroxide (OH⁻), hydrogenphosphate (HPO₄²⁻), water (H₂O), carbonate (CO₃²⁻), and trace constituents, the Ca/P molar ratio, crystal size and morphology, surface area, unit-cell parameters, crystallinity, and solubility of this HA were determined. This highly pure, homogeneous, and highly crystalline HA is certified as a National Institute of Standards and Technology (NIST) standard reference material, SRM 2910.