MC-ICP-MS高精度测定Li同位素分析方法

以不同浓度Li元素标准样品和K、Ca、Na、Mg、Fe单元素标准样品的混合溶液为研究对象,采用3根阳离子交换树脂（AG50 W-X8,200-400目）填充的聚丙烯交换柱和石英交换柱对Li进行分离富集,淋洗液分别为2.8 mol/L HCl、0.15 mol/L HCl以及0.5 mol/L HCl 30%乙醇,淋洗液体积小,仅为38 mL。分离回收率高,均大于97.6%。国际标样AGV-2（相对于IRMM-016）、BHVO-2（相对于IRMM-016）和IRMM-016（相对于L-SVEC）的δ7Li值分别为（5.13±0.94）‰（2σ,n=10）、（4.08±0.60）‰（2σ,n=4）和（0.038±0.73）‰（2σ,n=10）,与前人分析结果吻合,分析精度与国际同类实验室水平相当。并对比了马里兰大学同位素实验室和笔者实验室对同种岩石矿物样品的分析结果,在误差范围内具有很好的一致性。此外,对美国地质调查局提供的准标样NKT-1霞石岩（相对于IRMM-016）给出了定值,δ7Li值为（8.71±0.46）‰（2σ,n=4）。因此,本方法可用于测定天然样品的Li同位素组成。

Separation and Precise Measurement of Lithium Isotopes in Three Reference Materials Using Multi Collector-Inductively Coupled Plasma Mass Spectrometry

Lithium separation technique for three reference materials has been established together with precise determination of lithium isotope using a Neptune multi collector-inductively coupled plasma mass spectrometry （MC-ICP-MS）. The solutions of lithium element standard reference materials, potassium, calcium, sodium, magnesium and iron single element, were used to evaluate analytical methods applied. Three separate stages of ion-exchange chromatography were carried out using organic cation-exchange resin （AG 50W-X8）. Lithium was enriched for the three stages using different eluants, which are 2.8 M HCl, 0.15 M HCl and 0.5 M HCl in 30% ethanol, respectively. The columns for the first and second stages are made of polypropylene, and those for the third stage are made of quartz. Total reagent volume for the entire chemical process was 35 mL for three reference materials. The recovery yielded for the three stages is 98.9-101.2% with an average of 100.0%, 97.6-101.9% with an average of 99.9%, and 99.8-103.3% with an average of 100.6%, respectively. The precision of this technique is conservatively estimated to be ±0.72-1.04‰ （2σ population）, which is similar to the precision obtained by different authors in different laboratories with MC-ICP-MS. The δ7 Li values （ 7 Li/ 6 Li relative to the IRMM-016 standard） determined for andesite （AGV-2） and basalt （BHVO-2） are 5.68‰ （n=18）, 4.33‰ （n=18）, respectively. The δ7 Li value （ 7Li/6Li relative to the L-SVEC standard） determined for IRMM-016 is -0.01‰ （n=15）. All these analytical results are in good agreement with those previously reported. In addition, the results for the same kinds of samples analyzed at the MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, are consistent with those obtained at the Plasma Laboratory, University of Maryland, within analytical uncertainty. According to these experiment results, it is concluded that this proposed procedure is a suitable method for determining the lithium isotopic composition of natural samples.

丙氨酸氨基转移酶检测系统溯源性研究

目的建立深圳市龙华人民医院院检验科丙氨酸氨基转移酶(ALT)检测系统的溯源性,提高最终检测结果的准确性。方法依据《GB/T 21415-2008/ISO 17511:2003》中的国际标准溯源链式图自建该医院检验科溯源流程图;购买参考物质IRMM ERM AD 454,通过测定临床新鲜血清标本进行临床比对确保参考物质具有互通性,同时采用SPSS17.0进行统计学分析,以97%的预测区间和检测项目1/4CL IA'88总允许误差为标准,达到量值传递验证要求,进一步确定不确定度,完成量值溯源工作。结果通过该医院自建的溯源流程实验,证明丙氨酸氨基转移酶试剂盒的产品校准品与IRMM ERM AD 454之间存在互通性,按照不确定度计算公式得到产品校准品的不确定度,赋值表示为135±5U/L。结论该医院检验科自建溯源流程成功对产品校准品进行了赋值修正,提高了试剂检测结果的准确性。

中国境内上市公司网站投资者关系栏目实证研究

首先指出我国境内上市公司的投资者关系管理正处于起步阶段;其次界定了投资者关系和投资者关系管理的定义,设计了一个初步的投资者关系管理模型;最后在对 400家境内上市公司网站中设有投资者关系栏目的样本进行评价的基础上,客观地论证了我国境内上市公司网站投资者关系栏目的现状及存在问题,给出一个相对完整的投资者关系栏目。