光谱分析用中合金钢标准物质的研制

介绍了光谱分析用25Cr3Mo3NiNbZrA中合金钢标准物质的研制过程。采用合理的冶炼锻轧工艺,选取不同部位的样品进行均匀性检验,确定了16个元素的认定值及扩展不确定度,并进行了线性、一致性考察以及与国内外同类标准物质的比对。     

光谱分析用标准物质/样品均匀性不同检验规则比较及其不确定度评定

通常光谱分析用标准物质/样品均匀性检验采用方差分析、平均值法或极差法,但在实际应用中,当采用不同的方法时,有时可能得出相反的结论,本文以实例进行剖析说明并计算其不均匀性所引入的标准不确定度,同时对各种均匀性检验规则的特点进行了比较,指出方差分析法及平均值法优点在于不仅其数理统计意义清晰明确,而且便于最终不确定度评定与分析,推荐使用方差分析或平均值法.     

耐辐照玻璃成分分析标准物质的研制

采用高温熔融方法制备了玻璃成分分析标准物质.对标准物质的制备技术、均匀性检验、稳定性考察及定值不确定度进行了分析.研制的耐辐照成分分析标准物质具有良好的均匀性和稳定性,各组分不确定度均小于5％.     

20nm银粉末粒度标准物质的研制

研制了用于X射线小角散射仪校准的20 nm粉末粒度标准物质,并对标准物质的制备技术、均匀性检验、稳定性考察及定值不确定度进行了分析。研制的银粉末粒度标准物质具有良好的均匀性和稳定性,标准值为17.2 nm,相对扩展不确定度为6%。     

含氮铸铁光谱分析标准物质的研制

介绍一套含氮铸铁光谱分析标准物质的研制过程。结果表明，采用独特铸造工艺研制的该套含氮铸铁光谱分析标准物质具有良好的均匀性、成线性和稳定性，由9家实验室协同定值，确定了C、Si、Mn、P、S、Cr、Ni、Cu、V、Ti、Mo、Mg、Al、La、Sn、Ce、N等17种元素的标准值及其不确定度，定值准确、可靠。     

甲醇中丙烯酸乙酯溶液标准物质制备

研制特征量值为1 000μg/mL甲醇中丙烯酸乙酯溶液标准物质。分别利用气相色谱-质谱联用法、核磁共振波谱法和红外光谱法对丙烯酸乙酯标准品原料进行定性确认。采用质量平衡法对主成分含量进行量值核验，丙烯酸乙酯标准品纯度（质量分数）为99.842%，扩展不确定度为0.3%，量值在证书给出的不确定度范围内，因此采用证书标识量值作为原料标准值，证书中标识的不确定度作为原料不确定度。以丙烯酸乙酯标准品为原料，采用重量-容量法制备溶液标准物质，分别采用F检验和t检验对标准物质进行均匀性和稳定性检验，并对其定值结果的不确定度进行评定。结果表明，该标准物质均匀性和稳定性良好，有效期为12月，定值结果的相对扩展不确定度为2%(k=2)，可用于环境样品中丙烯酸乙酯分析方法的确认和评价以及仪器校准与检测质量控制。     

铜–铬–锆合金光谱分析用标准物质的研制

以电解铜和铜–铬、铜–锆中间合金为原材料,通过真空熔炼和热锻加工工艺,研制了铜–铬–锆合金光谱分析用标准物质。将样品分成4组,每组85块后,采用金相检验和光电直读光谱仪进行均匀性、稳定性和定值分析。从样品中随机抽取15块进行均匀性检验,经F检验表明,在95%的置信区间范围内样品均匀性良好;稳定性考察12个月,结果表明在考察期间内样品稳定性良好;标准物质样品经国内3家具有分析资质的实验室进行协作定值,并评定了定值结果的不确定。铜–铬–锆合金标准物质样品中Cr,Zr元素的相对扩展不确定度分别为0.015%~0.036%,0.019%~0.033%(k=2)。该标准物质达到了国家标准物质的技术要求,可用于有关铜–铬–锆合金产品中铬、锆元素的方法校准和质量控制。     

硬质聚氯乙烯氧指数标准物质的研制

研制硬质聚氯乙烯(硬质PVC)氧指数标准物质。对制备技术、均匀性检验、稳定性考察及定值不确定度进行了分析。研制的硬质PVC标准物质具有良好的均匀性和稳定性,定值数据呈正态分布,各实验室数据等精度。硬质PVC标准物质氧指数标准值为43．6％,扩展不确定度为0．7％。     

特种合金钢系列标准物质研制

介绍了特种合金钢系列标准物质的研制过程。采用合理的冶炼锻轧工艺,选取不同部位的样品进行均匀性检验,确定了15种元素的认定值及扩展不确定度,并进行了线性、一致性考察以及与国内外同类标准物质的比对。结果表明,本套特种合金钢系列标准物质的均匀性良好,定值准确且有良好的梯度分布。     

钛矿石与钛精矿X射线荧光光谱分析与化学分析用标准样品的研制

研制了钛矿石与钛精矿X射线荧光光谱分析与化学分析用标准样品。从国内外有代表性的矿区取点,采用了多级破碎、三维机械混筛工艺,确保了标准样品化学成分的均匀性,多家权威实验室用准确可靠的分析方法确定了16种化学成分的标准值和不确定度,实验表明,标准样品的线性与稳定性良好。该项目标准样品填补了国内外同类X射线荧光光谱分析标准样品的空白,已被国家检验检疫总局和国家标准化管理委员会批准为国家级标准样品。     

Accurate measurement of bromine contents in plastic samples by instrumental neutron activation analysis

Accurate measurements of bromine contents in plastic samples were made by the direct comparator instrumental neutron activation analysis (INAA). Individual factors affecting the measurements were comprehensively evaluated and compensated, including the volatility loss of bromine from standard comparators, the background bromine level in the filter papers used for preparation of the standard comparators, nuclear interference, γ-ray spectral interference and the variance among replicates of the samples. Uncertainty contributions from those factors were thoroughly evaluated and included in the uncertainty budgeting of the INAA measurement. ⁸¹Br was chosen as the target isotope, and the INAA measurements for bromine were experimentally confirmed to exhibit good linearity within a bromine content range of 10–170 μg. The established method has been applied to the analysis of eight plastic samples: four commercially available certified reference materials (CRMs) of polyethylene and polystyrene and four acrylonitrile butadiene styrene (ABS) samples prepared as the candidate reference materials (KRISS CRM 113-01-012, -013, -014 and -015). The bromine contents of the samples were calculated at three different γ-ray energies and compared, showing good agreement. The results of the four CRMs also showed good consistency with their certified values within the stated uncertainties. Finally, the bromine contents of the ABS samples were determined with expanded uncertainties (at a 95% level of confidence) between 2.5% and 5% in a bromine content range of 25–900 mg kg⁻¹.     

Molecular speciation of microparticles: application of pattern recognition techniques to laser microprobe mass spectrometric data

Attempts were made to enhance the ability of laser microprobe mass spectrometry (LAMMS) to identify molecular species in individual microparticles by applying pattern recognition methods. Principal component analysis (PCA) and canonical discriminant analysis were applied to LAMMS data for nickel-containing environmental particles. Detailed comparison of the two statistical methods demonstrated the utility of PCA. The successful application was highly dependent on the use of appropriate spectral normalization and feature extraction techniques prior to PCA. Although the test system involved only a small number of standard compounds, the LAMMS data were complicated by the effects of intra-particle heterogeneity common to environmental samples and by instrumental limitations. Pattern recognition techniques provided more accurate quantitative assignments of molecular species than were available by qualitative inspection of characteristic cluster ions or by simple spectral subtraction to compare particle data with a library of standard compounds. Results were substantiated by comparison with bulk analysis studies using wet chemical techniques.     

Variable alignment of high resolution data by cluster analysis

High resolution time-of-flight secondary ion mass spectrometry (HR TOF-SIMS) is a powerful surface analytical method. For complex samples, this technique may yield intricate spectra that are difficult to interpret visually. Chemometric methods are useful for data analysis. However, these methods require that spectra are represented in a matrix format. Variances in mass measurements caused by calibration or instrumental effects may present difficulties in properly aligning mass spectral peaks into the correct columns of the data matrix. Cluster analysis of resolution elements is proposed as an alternative approach to construct the data matrix. An automated method for optimizing the data alignment is presented and evaluated for standard steel samples.     

新型镁合金Mg-Al-Zn-Y光谱标准样品的制备和定值

采用双层安全炉熔炼镁合金和环壁式除渣法清除结晶器中的氧化皮和夹渣等技术,研制了新型镁合金Mg-Al-Zn-Y光谱标准样品.考察了标准样品的均匀性和稳定性,该标准样品有效期为5年.使用先进的数据处理软件(StndMtrl),对多家单位协作分析定值原始数据进行检验和计算,得到标准样品的标准值和标准偏差.用化学法对标准样品进...     

钛合金光谱分析用标准物质的均匀性检验

介绍钛合金光谱分析用标准物质均匀性检验的抽样、测试、检验及判断方法。钛合金光谱分析用标准物质中碳和铝的均匀性检验结果表明此两种元素在试样中的分布是均匀的。该方法已应用于钛合金光谱分析用标准物质的研制过程中。     

Application of k0-based internal mono standard instrumental neutron activation analysis method method for composition analysis of stainless steel clad sample

The k₀-based internal mono standard instrumental neutron activation analysis (INAA) method was used for the composition analysis of some irregular shape stainless steel (SS) samples of type SS 316M, which is used as fuel cladding in Indian fast breeder test reactor (FBTR). The method utilizes in situ relative detection efficiency using γ-rays of the activation products present in the sample for overcoming γ-ray self-attenuation. Samples were neutron activated using the thermal column as well as the core position of the reactor and the assay of radioactivity was carried out by high-resolution gamma ray spectrometry. The elements determined were Fe, Cr, Ni, Mo, Mn, Co, Cu, As and W. Since all the major elements (Fe, Cr, Ni, Mo and Mn) were amenable to NAA, the relative elemental concentrations with respect to Fe, obtained by this method, were converted to their absolute values by mass balance. The results were compared with specified compositions and found to be satisfactory. In order to validate these results obtained by the standard-less approach, sub samples of SS 316M in solution forms were analyzed by prevalent relative and k₀ methods of INAA, and results were found to be in good agreement. The accuracy of the internal mono standard INAA method has been evaluated by analyzing an alloy steel certified reference material, CRM 225/1 of British Chemical Standards (BCS).     

基于显微共聚焦拉曼光谱技术快速检测3种梭菌中肉毒梭菌

提出了一种基于显微共聚焦拉曼光谱技术的肉毒梭菌快速鉴别方法.利用共聚焦显微拉曼光谱技术(CRM)采集了肉毒梭菌、艰难梭菌和产气荚膜梭菌的拉曼光谱,比较了3种梭菌的平均拉曼光谱,采用基线校正、标准正态变换、Savitzky-Golay 5点平滑和最大最小值归一化预处理后,借助主成分分析(PCA)降维并提取特征变量,对样本...     

TC11钛合金光谱分析标准物质的研制

研制了TC11钛合金光谱分析标准物质,采用合理的熔炼和锻造工艺保证了标准物质的均匀性．经方差法和极差法检验,各元素均匀性良好。采用9家权威实验室协作定值,确定的标准值准确可靠,与国内外同类标准物质比对,结果表明,该套标准物质达到了同类标准物质国际先进水平。     

Speciation and instrumental neutron activation analysis for arsenic in water samples

Ground water samples obtained from West Bengal, India were analyzed for total arsenic and its inorganic species contents by instrumental neutron activation analysis (INAA). Two anion exchange separation methods using Dowex 1X8 in chloride and acetate forms were standardized for the speciation of As(III) and As(V) using radiotracers. The method by Dowex 1X8 in the acetate form was validated using synthetic mixtures of As(III) and As(V), and applied to water samples; the species concentrations were determined by INAA. The accuracy of the INAA method was evaluated by analyzing the NRCC CRM DORM-2 for total arsenic.     

Consideration of the uncertainty in the CRM value with the analysis of solid materials using atomic spectrometry

 The principles of the ISO "Guide to the expression of uncertainty in measurement" are applied to the analysis of solid materials by graphite furnace atomic absorption spectrometry. Assessment of trueness is achieved by the analysis of a certified reference material (CRM) under fixed instrumental conditions. For the evaluation of the method's uncertainty (as part of the validation) a model equation is derived, considering all significant contributions, including the uncertainty in the CRM value and the uncertainty in the CRM analysis. A concrete example is presented and discussed (soya flour as an unknown sample and CRM BCR rye grass). For routine analysis a pooled estimate from the validation experiment can be used, leading to an acceptable small uncertainty range even in the case of "duplicate determination". The test for trueness (acceptance) of the result of the CRM analysis is applied and the correction for detected bias is discussed. Received: 28 June 1998 · Accepted: 13 July 1998