低比表面积标准物质的研制

选择商品化的Al2O3颗粒作为低比表面积标准物质候选材料,利用交叉缩分方法对标准物质样品进行分装。经均匀性、稳定性(12个月)检验,标准物质样品具有良好的均匀性和稳定性。采用国际公认的氪气物理吸附BET方法,通过与德国BAM标准物质BAM-PM101比较测量的方式对标准物质样品进行定值(0.221 m2/g)。与国内外同类标准物质比较表明,研制的低比表面积标准物质GBW(E)130365填补了国内空白,其相对不确定度(5.9%)达到国际同类标准物质的先进水平。     

碳黑比表面积标准物质的研制

选择商品化的碳黑作为比表面积标准物质候选材料,利用交叉缩分的方法对碳黑样品进行分装。经均匀性、稳定性(18个月)检验,碳黑标准物质样品具有良好的均匀性和稳定性。按照国际公认的氮气物理吸附BET方法,联合测量能力经确认过的8家实验室对碳黑标准物质样品进行定值(104.6、29.9、8.96 m2/g)。与国内外同类标准物质比较表明:研制的3种碳黑比表面积标准物质的相对不确定度(2.1%、2.3%和3.2%)达到国际同类标准物质的先进水平。     

氮中43组分TO-14VOCs标准气体的研制

研制了浓度约为1×10~(-6)(mol/mol)氮中43组分TO-14 VOCs标准气体[GBW(E)062376]。该标准气体根据GB/T 5274严格按照配制气体标准物质的基本方法称量法制备及定值。利用研究开发的气质联用法对其进行了均匀性和稳定性检验。还将其与国际公认的同类标准气体进行了比对,并经国内最具权威性部门中国计量科学研究院进行检测验证。     

酸性橙II纯度标准物质的研制

质量平衡法是确定有机类标准物质纯度的经典方法,利用质量平衡法研制了GBW(E)100373酸性橙Ⅱ纯度标准物质,介绍了标准物质样品的制备、均匀性检验、稳定性检验、定值、不确定度评定及比对和验证等严格的研发程序。最终获得了纯度认定值为99.2%,相对扩展不确定度为1.0% (k=2)的酸性橙II纯度标准物质,可以在食品和化妆品分析中的仪器校准和方法评定等领域发挥重要作用。     

氮中甲硫醇、甲硫醚、二甲基二硫醚混合气体标准物质的研制

该文介绍瓶装1.00～20.0μmol/mol氮中3组分有机硫化合物混合气体标准物质的研制方法。以甲硫醇、甲硫醚、二甲基二硫醚等高纯气体和试剂为原料,进行纯度分析后,采用称量法制备定值,并使用气相色谱硫化学发光检测器对其均匀性和稳定性进行检验。实验结果表明,该标准物质的均匀性和稳定性满足F检验和t检验的要求,其定值的相对扩展不确定度为U=2.0%(k=2),有效期为12个月。该标准物质获得国家二级气体标准物质证书,编号为GBW(E)062461。     

GBW(E)100674乙腈中展青霉素溶液标准物质的研制

本课题研制了乙腈中展青霉素的溶液标准物质1种,并已成功申报为国家二级标准物质(GBW(E)100674)。该溶液标准物质以展青霉素纯度国家二级标准物质(GBW(E)100673)为原料,采用重量容量法配制。依据JJF1343-2012《标准物质定值的通用原则及统计学原理》的要求,本研究采用液相色谱法对乙腈中展青霉素溶液标准物质进行均匀性、短期稳定性和长期稳定性的评价。定值不确定度包含原料纯度、溶液配制、均匀性、短期稳定性和长期稳定性五个方面引入的不确定度。最终,该溶液标准物质GBW(E)100674的定值结果为100μg/m L,不确定度为2%。本研究研制展青霉素溶液标准物质的量值具有溯源性和准确性,可以支持国家食品安全检测的需要。     

总余氯标准物质研制北大核心CSCD

余氯是水质监测的一个重要指标,是评判水质好坏的重要参数。为此,研制了国家二级总余氯标准物质GBW(E)084725、GBW(E)084726。针对常用的总余氯测量方法,从中选取适合标准物质定值的测试方法,并对测试方法进行方法学研究。分别对2种浓度总余氯标准物质进行了均匀性和稳定性检验。方差检验F值均小于列表临界值,表明该标准物质均匀性良好。在6个月的稳定性考察期内,2种含量的标准物质在统计学上无明显变化,进行10天短期高低温模拟实验,2种含量的标准物质在统计学上也无明显变化,说明2种标准物质稳定性良好。采用氧化还原滴定法进行标准物质定值,量值分别为50 mg/L和500 mg/L,相对扩展不确定度分别为0.9%和0.5%。     

系列人胰岛素溶液标准物质的研制

本文介绍了6个水平人胰岛素溶液标准物质的制备、定值、均匀性和稳定性检验等研制过程.该系列标准物质以GBW09292胰岛素(人)纯度国家一级标准物质为原料,通过重量-容量法,采用天平准确称重并定容到容量瓶中,配制出6个水平的人胰岛素溶液标准物质候选物;接着在洁净环境下将标准物质候选物分装到棕色安瓿瓶中,每管分装500μL...     

异辛烷中的正十六烷标准物质的研制

介绍了异辛烷中正十六烷标准物质研制方法。采用称量-容量法对该标准物质定值,利用气相色谱法对定值结果进行了验证,同时考察了该标准物质的均匀性和稳定性,并与中国计量科学研究院研制的标准物质GBW(E)130102进行比对,标准物质定值结果为100ng/μL,相对扩展不确定度为3%(k=2),有效期为1年。该标准物质已成功取得国家二级标准物质证书,证书编号为GBW(E)130494。     

人血清中葡萄糖标准物质的研制

血糖是诊断和判别糖尿病的直接指标,标准物质是血糖检测结果准确可比的重要保障。研制人血清中6个不同浓度水平的葡萄糖标准物质的过程包括标准物质的制备、定值、均匀性、稳定性检验、不确定度评定以及互通性评价等内容。其中标准物质定值采用了两种不同原理的方法即同位素稀释-液相色谱-串联质谱法及同位素稀释-气相色谱-质谱法,准确测定人血清中葡萄糖的浓度,并重点分析了两种方法测试结果的差异及成因。人血清中葡萄糖标准物质的量值覆盖1.70～28.12 mmol/L,具有良好的均匀性和稳定性,已获得国家二级标准物质定级证书,编号为GBW(E)091140～GBW(E)091145,有望用于临床检验及相关领域对血清葡萄糖项目测量的质量评价等方面。     

Octadecyl immobilized surface for precipitate collection with a renewable microcolumn in a lab-on-valve coupled to an electrothermal atomic absorption spectrometer for ultratrace cadmium determination

Octadecyl immobilized surface was, for the first time, proved to be a superb precipitate-collecting medium. Surface charge effect was assumed to dominate the adsorption of cadmium hydroxide precipitate, facilitated by electrostatic interaction between the negatively charged C18 bead surface and positively charged cadmium hydroxide clusters. Residual silanol groups on the C18-immobilized silica surface did not contribute to precipitate adsorption. A novel procedure for ultratrace cadmium preconcentration was proposed by incorporating a renewable microcolumn in a lab-on-valve system. Cd(OH)(2) precipitate was adsorbed onto the C18 surface, which was afterward eluted with 20 microL of nitric acid (1%) and quantified with detection by electrothermal atomic absorption spectrometry. An enrichment factor of 28 and a limit of detection of 1.7 ng L(-1), along with a sampling frequency of 13 h(-1) were obtained with a sample consumption of 600 microL within the concentration range of 0.01-0.2 microg L(-1), achieving a precision of 2.1% RSD at the 0.05 microg L(-1) level. The enrichment factor was further enhanced to 44 by increasing the sample volume to 1200 microL. The procedure was validated by analyzing cadmium in three certified reference materials, that is, river sediment (CRM 320), sea lettuce (CRM 279), and frozen cattle blood (GBW 09140). Good agreement between the obtained results and the certified values was achieved.     

Slurry sampling-microwave assisted leaching prior to hydride generation-pervaporation-atomic fluorescence detection for the determination of extractable arsenic in soil

A flow injection-pervaporation method, where the sample was introduced as slurry, has been developed for the continuous derivatization and determination of arsenic in soil by hydride generation-atomic fluorescence spectrometry. The removal of arsenic is achieved with the help of a microwave digestor, which facilitates an on-line leaching in the flow injection manifold. Slurries, prepared by mixing the soil (particle size <65 microm) with 6 mol L(-)(1) HCl, were magnetically stirred for 3 min, and while stirring, the pump aspirated the aliquot and filled the loop (500 microL) of the injection valve. An industrial soil and five types of soil (sandy, clayey, slimy, limy, organic) were selected for the optimization of the leaching and determination steps of arsenic, respectively. The results obtained from three certified reference materials [stream sediment GBW 07311 (188 microg/mL As), river sediment CRM 320 (76.7 microg/mL As), and soil GBW 07405 (412 microg/mL As)] using direct calibration against aqueous standards demonstrate the reliability of the method. The relative standard deviation for within-laboratory reproducibility was 4.5%.     

菌落的等效性模拟及标准物质研究

菌落本身不稳定,不方便携带,不适合用作菌落计数器计量校准用标准物质。采用菌落的模拟图像来代表菌落,根据菌落的特点,将大小不一、分布不均的菌落图像加工成图片,等效模拟菌落总数和大小研制成模拟菌落标准物质。采用分层随机抽样的方法,进行均匀性和稳定性的研究,结果表明制备的模拟菌落标准物质具有良好的均匀性和足够的稳定性。通过人工计数和影像测量机对模拟菌落的总数、大小进行了定值并评定了不确定度。该系列标准物质便于存放、携带,已通过国家二级标准物质评审,编号为GBW(E)130586~GBW(E)130590,可用于菌落计数器的校准、分析方法评价等方面。     

苯系物溶液标准物质的研究

论述了苯系物溶液标准物质的研究工作 ,系统地介绍了标准物质原材料的选择、特性量值的测量方法、标准物质的制备方法、均匀性检验、稳定性考察以及定值测量。对样品的均匀性、测量的分散性及其他因素引入的不确定度分量分析和确定后 ,给出了整个测量过程不确定度的合成结果。对气相色谱法和液相色谱法所得到的实验结果进行了统计分析 ,其均匀性符合F检验和T检验 ,满足标准物质的技术规范。对苯系物溶液标准物质的稳定性进行了 2年的考察 ,证明该标准物质是稳定的 ,浓度值的不确定度为 2 8%。苯系物溶液标准物质已被批准为国家一级标准物质     

河流沉积物环境放射性标准物质的研制

研制出一种天然基质的河流沉积物环境放射性标准物质。由多个实验室用多种准确可靠的方法对其中９种天然的和人工的放射性核素进行了定值。介绍样品制备、均匀性及稳定性检验、核素定值方法和定值结果。     

Species-specific GC/ICP-IDMS for trimethyllead determinations in biological and environmental samples

An accurate and sensitive species-specific isotope dilution GC/ICPMS method was developed for the determination of trimethyllead (Me3Pb+) in biological and environmental samples. A trimethyllead spike was synthesized from 206Pb-enriched metallic lead by reaction of lead halide with methyllithium and subsequent formation of trimethyllead iodide. The isotopic composition of the spike solution was determined by GC/ICPMS after derivatization with tetraethylborate, and its concentration was determined by reverse isotope dilution analysis. The species-specific GC/ICP-IDMS method was validated by reference material CRM 605 (urban dust) certified for Me3Pb+. The method was also applied to determine the Me3Pb+ content in six biological reference materials (DORM 2, CRM 278, CRM 422, CRM 463, CRM 477, MURST-ISS-A2) and one sediment reference material (CRM 580) for which no certified values of this species exist. The Me3Pb+ concentrations in the biological reference materials vary in the range of 0.3-17 ng g(-1) (as Pb) except for the Antarctic Krill (MURST-ISS-A2), where the concentration was less than the detection limit of 0.09 ng g(-1), which was also found for the sediment. Up to 20% of total lead was methylated in the biological reference materials, whereas much higher methylation fractions were found for mercury. The method was also applied to seafood samples purchased from a supermarket with Me3Pb+ concentrations in the limited range of 0.3-0.7 ng g(-1). On the contrary, the portion of methylated lead in these samples varied over more than 2 orders of magnitude from 0.02 to 7.5%.