石墨炉原子吸收光谱法测定大鼠血清中硒

通过考察不同基体改进剂效果,提出了以硝酸锶和硝酸钯做为混合基体改进剂。建立了用石墨炉原子吸收法测定牛血清和大鼠血清中痕量硒的分析方法。线性范围为0-120ng/mL,硒的检出限为0．095ng／mL,方法用于标准牛血清测定。结果与标准值基本吻合,大鼠血清测定标准加入回收率为102％。     

塞曼石墨炉原子吸收法直接测定血清中的硒

采用硝酸钯为硒的基体改进剂，用塞曼效应扣除背景，对消化后的血样直接进行测定。该法的检出限为6．0ng/mL，线性范围10ng/mL－136ng/mL，回收率为94．8％－102．5％。     

平台石墨炉原子吸收法直接测定高温镍基合金中硒

研究了基体改进剂及其用量,硒的灰化、原子化和出现温度,以及近20种共存离子的干扰。采用镍和钯混合液作基体改进剂,硒的灵敏度高,抗干扰能力强,不需要分离样品基体,可以采用平台石墨炉法直接测定高温镍基合金中硒。     

多阶半微分阴极溶出伏安法测定痕量硒(Ⅳ)的研究

阴极溶出伏安法测定痕量硒已有报导^[1~5],但准确度不佳,灵敏度还嫌不够。本文研究了盐酸和铜体系测定硒,在适宜条件,测定硒的浓度范围为0.04～20ng/mL,检测限为pg/mL级,硒含量在0.14ng/mL,变动系数小于10％。用拟定的方法测定了低硒地区水样及含硒量较高的粮食和人发,均获得了满意结果。     

激光热透镜光谱分析法同时测定铜、钴和镍研究

基于2-(5-NO2-吡啶-2-偶氮)-1-羟基-8-氨基萘-3，6-二磺酸与铜(Ⅱ)、钴(Ⅱ)和镍(Ⅱ)反应酸度的差异及热透镜信号强度的加和性，建立了激光热透镜光谱法同时测定铜、钴和镍的新方法。测定铜、钴和镍的线性范围依次为0～200ng/mL、0～200ng/mL和0～100ng/mL，检出限依次为2ng/mL，2．5ng/mL和1ng/mL。方法已用于合成样品及人发样中铜、钴和镍的同时测定。     

碱性体系氢化物发生-原子荧光光谱法测定矿物中的痕量硒

对碱性氢化物发生－原子荧光光谱法测定痕量硒的方法进行了探讨,研究了体系的最佳实验参数。与常规酸性 体系氢化物发生－原子荧光光谱法比较,本法能有效地消除大量铜、铁、钴、镍等过渡族元素的干扰,样品可不经分离直接进行测定。经过国家标样的分析验证,其测定值与推荐值吻合。方法的检出限为0.55ug/L,相对标准偏差为4.12％;原子加入回收率为99.8%.     

原子吸收法测定精硒中碲铅铋锑铜铁镍镁

以二氧化硒形式挥发除去主体硒后,用原子吸收光度法,同时测定精硒中碲、铅、铋、锑、铜、铁、镍、镁八种元素。方法的测定范围:碲、铅、铋、锑为0.0005％～0.003％,铜、铁、镍、镁为0.0002％～0.002％。试样加标回收率在90％～105％之间。方法简便,结果满意。     

萃取—石墨炉原子吸收法测定粮食中硒

本文介绍一种灵敏而准确的方法用于测定粮食中硒。于APDC—MIBK体系中加入微克量铜或镍进行协同萃取,不仅可提高测定硒的灵敏度,而且由于生成较稳定的硒化物,可使硒的灰化温度提高到1200℃而不致挥发损失,较大程度地提高了测定硒的准确度。在涂锆石墨管中可准确测定粮食样品中0.045—0.307μg/g的硒。回收率达96—102%,相对标准偏差为3.3%,检出限为0.010μg/g硒。     

石墨炉原子吸收光谱法测定磷时基体改进剂的应用研究

本文阐述几种基体改进剂测定磷的效果,发现Pd/Ca混合基体改进剂对测定植物和动物组织中磷最理想,利用氘灯扣背景,其特征量为8.2ng,吸光度线性范围为0～0.220,磷含量为0.144％和1.35％时,相对标准偏差为2％左右,精密度好,抗干扰能力强,测定茶树叶和贻贝中磷比较理想。     

钯—抗坏血酸基体改进剂石墨炉原子吸收光谱法测定食品中的痕量硒

本文用塞曼效应石墨炉原子吸收法测定食品中的硒，研究了各种基体改进剂对硒信号的改进效应，找出最佳的改进剂钯－抗坏血酸，使硒的灰化和原子化都能达到较高温度，在提高灵敏度，降低干扰方面也取得较好的效果。本方法操作简单、快速、灵敏度高，能有效地测定食品中的痕量硒。方法的回收率在９５．６％－１０４．０％之间，其相对标准偏差为３．０％，检出限为４．４８５ｎｇ／ｍＬ。     

基体石墨的孔隙结构及其对单质Ag扩散的影响

高温气冷堆燃料元件的基体石墨是一种多孔复合材料,是燃料元件的主要组成部分,其结构影响燃料元件的性能和裂变产物在燃料元件中的扩散。 本文利用压汞法表征基体石墨的孔隙结构,并讨论了基体石墨制备工艺中最大压制压强与热处理过程对孔隙结构的影响。 结果表明,基体石墨大孔孔径分布为6001900 nm,高温热处理使基体石墨的总孔隙率、中值孔径、大孔孔容均减小;基体石墨热处理样品的大孔孔容随最大压制压强的增加而呈线性减少,热处理过程单质Ag在石墨基体中的扩散速度与大孔孔容变化具有正相关性。     

Direct determination of boron in a cobalt-based alloy by graphite furnace-atomic absorption spectrometry

A matrix modifier composed of nickel and zirconium, and a graphite tube treated with zirconium solution were proposed for the determination of boron in cobalt-based alloys by graphite furnace-atomic absorption spectrometry. The effects of this matrix modifier and the treated graphite tube were studied, and the combination of 60 mug of nickel and 20 mug of zirconium as matrix modifier, and a graphite tube soaked with 10 g 1(-1) of zirconium solution were found to give the highest analytical sensitivity. The interference effects of major components (cobalt) and eight minor components (chromium, nickel, tungsten, iron, tantalum, molybdenum, titanium, aluminium and manganese) were studied. Boron in four cobalt-based alloys was determined by graphite furnace-atomic absorption spectrometry employing the proposed matrix modifier and the treated graphite tube, without the preseparation of matrix. The relative standard deviation was 3.3% for 0.048% of boron. A characteristic mass was 500 pg.     

Effect of atomizer surface type on the quantitation of molybdenum and ytterbium by electrothermal atomization atomic absorption spectrometry

The effect of pyrocoated graphite, uncoated graphite, metal-carbide, and metal atomization surfaces on the quantitation of molybdenum and ytterbium by electrothermal atomization atomic absorption spectrometry was investigated. The peak shape was affected by heating rate and the different surfaces gave different shapes. Except for the case of uncoated graphite, the sensitivities and detection limits were similar for all surfaces. In a sodium chloride matrix it is preferable to use uncoated graphite for molybdenum because an ashing stage greater than the boiling point of sodium chloride can be used without loss of molybdenum. Tube lifetime depended on atomization temperature, atomization time and the matrix.     

The application of metal-coated graphite tubes to the determination of trace metals in biological materials: I. The determination of lead in blood using a tungsten-coated graphite tube

A new technique is introduced in trace metal determinations in biological materials by coating the graphite tube with tungsten by a highly reproducible process. This coating appeared to be responsible for the prevention of residue formation that occurred in untreated graphite tubes when lead in blood was analyzed. The life of the graphite tube was thus increased by about 300% for this matrix.     

锡石墨炉原子化机理研究

本文考察了盐酸、硫酸、硝酸、亚硒酸及硼酸中锡的石墨炉原子吸收特性,对锡在不同基体中的原子化过程进行了初步探讨。发现硼酸是石墨炉法测定锡时的一种较好的化学改进剂;1%的硼酸加入可克服一定含量的硫酸与盐酸的干扰。并利用XRD与XPS对硼酸与锡共存时的石墨表面进行了结构与状态分析。提出了硼酸与锡共存时,锡的原子化历程。     

Direct determination of traces of copper,zinc, lead,cobalt, iron and cadmium in bovine liver by graphite furnace atomic absorption spectrometry using the solid sampling and the platform techniques

A simple and rapid method is described for direct determination of traces of Cu, Zn, Pb, Co, Fe and Cd in NBS bovine liver, SRM 1577, by graphite furnace atomic absorption spectrometry. The solid sampling technique was used, thereby avoiding the dilution factor involved in the solution technique, and also the risk of contamination from the environment in sample handling and from reagents, solvents and vessels. The organic matrix was burnt off and removed by using a well-defined selective volatilization technique combined with the analyte modification technique. Also, the effect of the platform technique in removing matrix interferences was studied using an anisotropic pyrolytic graphite platform inside the commercial graphite tube. The results of the “with platform” and the “without platform” techniques were equally accurate, but the “with platform” technique gave better precision.     

衬钽管石墨炉原子吸收法测定痕量镓时基体改进剂的研究及应用

提出用钒和铜混合基体改进剂衬钽管石墨炉原子吸收测定镓的方法。衬钽管使镓的灵敏度提高6倍左右,钒和铜混合基体改进剂不仅能进一步提高灵敏度,而且能提高灰化温度,降低原子化温度,增强抗干扰能力。测定 GSD 标准样品中的镓时,不需对样品进行预分离即可直接进行测定,结果与参考值相符。     

Transport properties of graphite/epoxy composites: Thermal, permeability and dielectric characterization

In this study nanocomposites were prepared by dispersing three different grades of graphite particles, expanded graphite, commercial graphene nanoplatelets and natural graphite, in a commercial epoxy matrix. Dielectric properties, thermal conductivity and permeability to oxygen of the composites were studied and compared to those of the unfilled epoxy matrix. An increase of all properties is obtained using expanded graphite, suggesting the presence of a good dispersion of the filler in the matrix and a strong polar interactions of the filler with the matrix, attributed to the partially oxidised surfaces of the expanded graphite. All the measured transport properties were fitted with simple mathematical models obtaining good agreement between the experimental results and theoretical predictions. The model parameters were related to the aspect ratio of the filler, defined as the ratio between the in-plane average dimension and the thickness of the reinforcement. An aspect ratio between 1250 and 1550 indicates that graphite thin platelets (or graphene stacks), characterized by a thickness of the order of a few tens of nanometers, were dispersed in the epoxy matrix.     

石墨炉原子吸收法测定钒的研究

本文比较了在标准石墨管,热解涂层和全热解石墨管中钒的吸收信号形状。用全热解石墨管和EDTA铵盐作基体改进剂,直接测定水系沉积物中痕量钒。方法的特征量为61pg/0.0044A。