中国陆架沉积物标准物质研制

报道了我国研制的2个大陆架沉积物标准物质MS-E1,MS-S1。MS-E1和MS-S1的原样分别取自东海和南海。样品经风干、破碎,球磨制备成均匀的粉体样品。均匀性采用高精度的X射线荧光光谱法检验。样品的化学组分采用国内外多实验室协同分析方式定值,有7个国内实验室和9个国外实验室参加了合作分析。测试组分均为67个,分别有43和42个组分定为保证值,8和9个组分作为参考值。全组分百分总和分别为99.8%和99.6%。经2年多的试用,2个标准物质已于2005年被国家计量部门批准为国家一级标准物质,其编号分别为:GBW07335和GBW07336。     

富钴结壳铂族元素超细标准物质的研制

2个富钴结壳铂族元素(PGEs)标准物质MCPt-1和MCPt-2的原样分别由中国和俄罗斯取自中太平洋海山和西太平洋麦哲伦海山区.样品经风干、选配,先经球磨制备成74 μm(200目)粉体样品,再用气流磨将其进一步加工成具有超细粒度的均匀样品.采用激光粒度仪检测样品的粒度分布,其平均粒度分别为1.8和1.5 μm(约2 000目).采用高精度的X射线荧光光谱法(XRF)和电子探针方法分别检验了6个主、次元素在mg和μg取样量水平上的均匀性,用LA-ICP-MS检验了包括Pt在内的40多个痕量元素在μg量水平上的均匀性.样品采用锍镍火试金和Carius管预富集和酸溶消解,除Rh外均采用同位素稀释电感耦合等离子体质谱测定(ID-ICP-MS),确定了MCPt-1和MCPt-2中6个铂族元素的标准值;采用XRF和ICP-AES、ICP-MS方法相结合给出了62个主、次和痕量元素的信息值.最小取样量分别为1 g(测定PGEs)和2 mg(测定其他元素).     

乳粉中硝酸盐、亚硝酸盐分析标准样品研制

研制乳粉中硝酸盐、亚硝酸盐分析标准样品。获得原料并确认后，对原料添加目标物，混匀，喷雾干燥，分装，包装制成标准样品。对样品进行均匀性、稳定性检验，通过多家实验室联合定值的方式对样品进行定值，从而获得标准值及其不确定度。样品中硝酸盐、亚硝酸盐均匀性检测数据经F检验在95%置信水平时单元件不具有统计显著性，表明样品是均匀的；样品稳定性检测数据经t检验，表明样品在-20℃保存条件下18个月内量值稳定；对8家有能力的实验室联合定值数据统计分析得到样品中硝酸盐标准值为22.4 mg/kg，不确定度为0.95 mg/kg(k=2)；亚硝酸盐标准值为23.0 mg/kg，不确定度为0.93 mg/kg(k=2)。样品均匀性、稳定性、赋值和不确定度评估等均符合有证标准样品的要求，能够满足预期用途。     

荧光检定用镍铬合金标准物质的研制

对荧光检定用镍铬合金标准物质的制备技术进行了研究,并考察了标准物质的均匀性和稳定性,分析了定值不确定度.经检验,该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,各实验室定值数据等精度.镍、铬含量的标准值分别为68.29%和28.35%,定值结果的相对扩展不确定度分别为0.7%和2%(k=2).     

吡虫啉标准样品的研制

采用重结晶法,以工业品为原料制备吡虫啉标准样品,利用高效液相色谱法测定其纯度并作为均匀性检验方法和定值方法,制得的标准样品均匀性、稳定性检验合格。该标准样品的标准值为(99.47±0.085)%。     

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...     

低温封接玻璃成分分析标准物质的研制

研制了低温封接玻璃成分分析标准物质,对标准物质的制备技术进行了研究。分别用F检验和t检验法对研制的标准物质进行了均匀性和稳定性检验,结果表明,研制的低温封接玻璃标准物质具有良好的均匀性和稳定性。采用6家实验室进行协作定值,对定值结果的不确定度进行了评定。各组分定值结果的相对扩展不确定度均小于5%(k=2)。     

水污染监测用水合肼标准样品的制备与量值评价

研制了水污染监测用水合肼标准样品。介绍了试剂的验证、均匀性和稳定性检验、分析定值和测定数据的统计检验等研制方法。采用重量法制备,用国家标准分析方法对样品进行均匀性和稳定性研究;并进行不确定度评估;水合肼标准样品的均匀性良好,至少可稳定30个月以上;标准值为50.0μg/L,相对扩展不确定度为2.2%(k=2)。     

牛磺酸标准物质的研制

研制了牛磺酸标准物质。采用红外光谱(IR)法对牛磺酸进行定性,经均匀性初检后分装成200瓶样品,利用超高效液相色谱(UPLC)及高效毛细管电泳(HPCE)两种不同原理的方法进行定值,从样品中随机抽取15瓶采用超高效液相色谱(UPLC)法进行了均匀性检验,经F检验表明在95%的置信区间范围内样品均匀性良好,稳定性考察按照短期稳定性(1个月)和长期稳定性(12个月)分别进行,结果表明在考察期间样品稳定性良好。评定了定值结果的不确定度,牛磺酸标准物质定值结果为99.6%,相对扩展不确定度为0.5%(k=2)。     

双相不锈钢等六种不锈钢光谱分析校正用标准样品的研制

研制了6种光谱分析校正用的不锈钢标准样品,包括五种奥氏体不锈钢和一种双相不锈钢.此6种不锈钢的化学成分设计参照以下牌号的钢种:0Cr18Ni9、00Cr19Ni10、0Cr17Ni12Mo2、00Cr17Ni14Mo2、0Cr18Ni10Ti及00Cr23Ni5Mo3N.在冶炼、浇铸、轧制及锻造等操作中采取了多种工艺措施,保证了材料的规格和均匀性.由国内5家具有资质的分析实验室参与协作定值.定值元素包括不锈钢样品中的主要合金元素及部分杂质元素总共迭18项(C,Si,Mn,P,S,Cr,Ni,Cu,Mo,V,Co,Ti,Sn,As,W,Al,Nb,N等).分析数据的统计处理采用数据统计软件,并按国内外相关标准的规定进行,文中给出了上述18项元素的标准值及其不确定度.此6种标准样品的有效期定为10年.     

Solid sampling in analysis of animal organs by two-jet plasma atomic emission spectrometry

A study of high-power two-jet plasma capabilities for the direct multi-elemental analysis of animal organs was undertaken. The experimental conditions chosen allow the direct analysis of different animal organs after drying and grinding to powder (particle size 20–200 μm). It was found that evaporation efficiency of the samples depends on the particle size and thermal stability of tissues and can be improved by reduction of a carrier gas flow. Calibration samples based on graphite powder and a tenfold dilution of powdered samples with buffer (graphite powder containing 15% NaCl) were used. 5–10 mg of the sample was quite enough to get the detection limits of elements at the level of 0.1–10 μg g^? 1. A prior carbonization procedure (not ashing) makes it possible to decrease the detection limits of elements by an order of magnitude. The validation of the techniques was confirmed by the analysis of certified reference materials NIST 8414, BCR 278R and NCS ZC 81001 as well as by using different sample preparation procedures.     

Simple solvent extraction technique for elimination of matrix interferences in the determination of methylmercury in environmental and biological samples by ethylation-gas chromatography-cold vapor atomic fluorescence spectrometry

A solvent extraction technique involving no critical clean-up steps was developed for the determination of methylmercury (MeHg) in environmental and biological samples by aqueous phase ethylation, room temperature precollection, gas chromatographic separation and cold vapor atomic fluorescence spectrometric detection. Samples were first digested with KOH-methanol. then acidified prior to extraction with methylene chloride. MeHg was back-extracted from the solvent phase into water prior to aqueous phase ethylation. Recoveries close to 100% were obtained with RSDs less than 5% for all samples analyzed, making direct standardization possible. The detection limits were about 0.08 ng g(-1) when analyzing 0.1 g of dry sea plant homogenate and 0.02 ng g when analyzing 0.5 g of wet sediment samples. Various certified reference materials and intercomparison samples, including sediments, sea plants and tissues, were analyzed, and the results were in good agreement with the certified values. The technique was applied to the determination of MeHg in both sea plants from the Atlantic and the red blood protein of dolphins from the Mediteranean Sea. in sediments from the Mediterranean Sea and Minnesota rivers and in soils from different origins. Concentrations of MeHg in dolphin red blood protein samples were as high as 300 ng g(-1).     

Estimation of the minimum uncertainty of DNA concentration in a genetically modified maize sample candidate certified reference material

Homogeneity testing and the determination of minimum sample mass are an important part of the certification of reference materials. The smallest theoretically achievable uncertainty of certified concentration values is limited by the concentration distribution of analyte in the different particle size fractions of powdered biological samples. This might be of special importance if the reference material is prepared by dry mixing, a dilution technique which is used for the production of the new and third generation of genetically modified (GMO) plant certified reference materials. For the production of dry mixed PMON 810 maize reference material a computer program was developed to calculate the theoretically smallest uncertainty for a selected sample intake. This model was used to compare three differently milled maize samples, and the effect of dilution on the uncertainty of the DNA content of GMO maize was estimated as well. In the case of a 50-mg sample mass the lowest achievable standard deviation was 2% for the sample containing 0.1% GMO and the minimum deviation was less than 0.5% for the sample containing 5% GMO.     

Estimation of the minimum uncertainty of DNA concentration in a genetically modified maize sample candidate certified reference material

Homogeneity testing and the determination of minimum sample mass are an important part of the certification of reference materials. The smallest theoretically achievable uncertainty of certified concentration values is limited by the concentration distribution of analyte in the different particle size fractions of powdered biological samples. This might be of special importance if the reference material is prepared by dry mixing, a dilution technique which is used for the production of the new and third generation of genetically modified (GMO) plant certified reference materials. For the production of dry mixed PMON 810 maize reference material a computer program was developed to calculate the theoretically smallest uncertainty for a selected sample intake. This model was used to compare three differently milled maize samples, and the effect of dilution on the uncertainty of the DNA content of GMO maize was estimated as well. In the case of a 50-mg sample mass the lowest achievable standard deviation was 2% for the sample containing 0.1% GMO and the minimum deviation was less than 0.5% for the sample containing 5% GMO. Received: 5 December 2000 / Revised: 14 March 2001 / Accepted: 19 March 2001     

Direct determination of Cu and Zn in fruit juices and bovine milk by thermospray flame furnace atomic absorption spectrometry

In the present work, thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) was employed for Cu and Zn determination in bovine milk and fruit juice samples without any pretreatment. TS-FF-AAS system was optimized and a sample volume of 300 μl was injected into the carrier stream (0.014 mol l⁻¹ HNO₃ at a flow rate of 0.4 ml min⁻¹), and it was introduced into a hot Ni tube. The detection limits obtained for Cu and Zn in aqueous solution were 2.2 and 0.91 μg l⁻¹, respectively, and 3.2 μg l⁻¹ for Cu in a medium containing water-soluble tertiary amines. The relative standard deviations varied from 2.7 to 4.2% (n=12). Sample preparation was carried out by simple dilution in water or in water-soluble tertiary amines medium. Accuracy was checked by performing addition-recovery experiments as well as by using reference materials (whole milk powder, non-fat milk powder, and infant formula). Recoveries varied from 97.7 to 105.3% for Cu and Zn. All results obtained for reference materials were in agreement with certified values at a 95% confidence level.     

Preparation and preliminary certification of two new Polish CRMs for inorganic trace analysis

Preparation and characterization of two new reference materials of biological origin, namely: Tea Leaves (INCT-TL-1) and Mixed Polish Herbs (INCT-MPH-2) is described. The raw materials were ground in an agate ball mill, sieved through a nylon sieve, collecting fraction of particle size: Æ£67 ·m, and carefully homogenized. Preliminary homogeneity testing by XRF method and final checking of homogeneity by NAA after distribution of the materials into containers revealed that they are sufficiently homogeneous at least for sample size ≥100 mg. Both materials were prepared in amounts exceeding 40 kg and certified on the basis of a worldwide interlaboratory comparison, in which 109 laboratories from 19 countries participated. The method of data evaluation leading to assignment of certified values was essentially the same as that used previously in this Laboratory, but supplemented by additional data from the analysis of a CRM which was sent to the participants and analyzed by them along with the candidate reference materials. In addition the results for a few elements by very accurate developed methods in this Laboratory were obtained and used to support the certification process. Analytical uncertainties and stability uncertainties were quantified to arrive at combined uncertainties of the certified values. So far 18 elements in INCT-TL-1 and 21 in INCT-MPH-2 could be certified.     

Use of sodium dodecyl sulfate as an antifouling and homogenizing agent in the direct determination of heavy metals by anodic stripping voltammetry

The effectiveness of the anionic surfactant sodium dodecyl sulfate (SDS) for suppressing adsorption interferences in anodic stripping voltammetry (ASV) was investigated. The samples included fruit juices, wine, beer, milk powder and waste water, and the analytes were cadmium, lead and copper. In most of the samples, the ASV signals were severely depressed or even absent due to electrode fouling, but addition of SDS in concentrations up to 10 g L(-1) proved effective in restoring the ASV response. By using SDS as an interference suppressor, the content of lead and copper in a milk powder reference material was determined, and the results were in agreement with the certified values. In this determination, which could not have been performed without SDS, the surfactant also served as a homogenizing agent, preventing separation of the sample components. The effect of SDS was explained by the interaction of the surfactant with the electrode surface and with the constituents of the sample matrix.     

X射线荧光光谱法分析镁砂的主次成分

采用镁砂标准样品作为校准样品,建立了熔融制样X射线荧光光谱法测定镁砂中MgO,Al2O3,SiO2,CaO,P2O5,Fe2O3的方法。采用熔融法为样品片和校准片的制备方法,选择四硼酸锂-偏硼酸锂（67＋33）为助熔剂,1.00mL LiBr溶液为脱模剂,熔融温度为1 100℃,熔融时间20min。对镁砂样品测定的相对标准偏差（RSD）小于3%,对不同镁砂标准样品进行测定,方法的测定结果与认证值相吻合。     

Single granular activated carbon microextraction and graphite furnace atomic absorption spectrometry determination for trace amount of gold in aqueous and geological samples

A new and simple method was developed for preconcentration trace amount of gold in aqueous and mineral samples. The method was based on the sorption of gold on granular activated carbon (AC) in acidic medium (hydrochloric acid) and subsequently direct determination by graphite furnace atomic absorption spectrometry (GFAAS). A small particle of adsorbent was delivered to small volume of sample. After extraction, AC removed and analyzed directly by GFAAS. Several factors influencing the extraction efficiency, such as the hydrochloric acid concentration, sample volume and extraction time were studied as well as effect of potential interfering ions. The preconcentration factor 50 was obtained. The limit of detection (LOD) of gold in water and soil samples was 0.007 μg L^− 1 and 0.9 ng g^− 1, respectively. The proposed method was applied successfully to the determination of trace amount of gold in environmental and geological samples. In order to validate the developed method, two certified reference materials: Platinum Ore (SARM-7B) and Copper Ore Mill Heads (No. 330) were analyzed and the determined values obtained were in good agreement with the certified values and recovery was obtained in the range of 80-118%. The relative standard deviations (RSD) for the spiking levels of 0.5 μg L^− 1 in the real samples was 4%, (n = 15).     

Multielement determination of typical diet reference materials by neutron-induced prompt gamma-ray analysis using k 0 standardization

Multielement determination in reference materials of diet and its relatedsamples has been studied by a k 0 based neutron-induced prompt gamma-ray analysis(PGA) by using cold and thermal guided neutron beams of JRR-3M at JAERI. Hydrogen,B, C, N, Na, S, Cl, K and Ca were determined in the reference materials ofNIES and NIST typical diet and milk powder samples. Analytical results ofthe NIST Standard Reference Materials agreed with the certified values towithin 7%.