校准曲线的回归与化探样品中痕量金分析准确度间的关系

本文针对日立180—80偏振塞曼石墨炉原子吸收法测定化探样品中痕量金,出现低含量样品测量值为负值的情况,探讨其引起的主要原因及其解决的基本途径。     

石墨炉原子吸收法测定化探样品中痕量金——石墨管使用次数对分析准确度的影响

本文报道了普通石墨管在化探样品中痕量金测试过程中,分析准确随石墨管使用次数的增加而变化的现象,研究了其引起的主要原因,简述了这类问题解决的办法。     

聚氨酯泡沫塑料分离富集石墨炉原子吸收光谱法测定痕量金

<正>初步认为泡沫塑料吸附机理是由于极性基团的吸附作用和胺基离子的交换作用。吸附金的泡沫塑料大都采用聚胺酯泡沫塑料,也可采用聚氨醚泡沫塑料。     

石墨炉原子吸收光谱法测定痕量金—测量方式对分析准确度的影响

本文报道了用不同厂家的仪器、不同种类的石墨管,不同测量方式对石墨炉原子吸收测定地球化学样品中痕量金分析准确度的影响,研究了其影响的主要原因。     

原子吸收分析测定矿石中的金

由于金在矿石中的含量很低,根据矿样的性质采用不同的预处理、溶样、分离、富集、吸附、灼烧和测定方法。矿石中金的测定有铅试金富集原子吸光谱法、活性炭富集碘量法、活性炭富集原子吸收光谱法、活性炭富集崔化光度法、泡沫塑料富集原子吸收光谱法、鳌合树脂富集原子吸收光谱法、甲基异丁基甲酮萃取无火焰原子吸收光谱法、重量法、火试金法等等。活性炭富集原子吸收光谱法,常用王水和稀王水溶解试样,通过多次分析测定,我认为用稀王水溶解的试样,分析测定结果简便、准确。     

石墨炉-原子吸收法测定非合金钢和低合金钢中痕量铅

建立石墨炉-原子吸收法测定非合金钢(碳素钢)和低合金钢中痕量铅的分析方法,并优化消解用酸、介质酸度、灰化温度、原子化温度等条件参数,考察铁基体和共存元素的干扰影响.确定的最佳工作条件和试验方法如下:石墨炉的灰化温度为500℃,原子化温度为2100℃,分析谱线波长为283.3 nm.样品称取0.125 g,采用硝酸(1+...     

汽油含铅量测定方法的研究——石墨炉原子吸收法

国家标准ＧＢ Ｔ 80 2 0 - 87《汽油铅含量测定 (原子吸收光谱法 )》 ,是将汽油试样用甲基异丁基甲酮稀释 ,加入磺和季铵盐与烷基铅化合物反应使之稳定。以氯化铅为标样 ,用火焰原子吸收光谱法测定试样中铅含量。采用上述处理方法 ,虽然稳定性高 ,重现性好 ,但灵敏度低 ,成本高 ,毒性大 ,会造成环境污染 ,还特别繁琐。本方法改善了以上方法的弊端。一、测定方法1 方法概要石墨炉原子吸收法测定铅含量是较灵敏的方法 ,可直接定性样品为有无铅汽油。有铅汽油 ,是以氯化铅为标样 ,用石墨炉原子吸收光谱法 ,在波长 2 83 3纳米处 ,测定试样中铅含…     

仪器条件对石墨炉原子吸收法测定地质样品中金的影响

建立一种快速、简便、准确的石墨炉原子吸收法测定地质样品中金含量的方法。通过改进仪器参数的方式，如加样、升温程序等，寻找最佳检测条件，制定检测方法，确立检测程序；对检测参数进行改进后，检测水平提高，准确度、精密度好，标准物质测定结果满意；改良后，该法简便快速、准确性高、重复性好，取得测定地质样品中金的满意结果。     

面制品中铝的测定方法样品处理的改进

铝是一种低毒金属元素,它并非人体需要的微量元素,不会导致急性中毒,但食品中含有的铝超过国家标准就会对人体造成危害。人体摄入铝后仅有10%-15%能排泄到体外,大部分会在体内蓄积,与多种蛋白质、酶等人体重要成分结合,影响体内多种生化反应,长期摄入会损伤大脑,导致痴呆,还可能出现贫血、骨质疏松等疾病,尤其对身体抵抗力较弱的老人、儿童和孕妇产生危害,可导致儿童发育迟缓、老年人出现痴呆,孕妇摄入则会影响胎儿发育。     

分散液液微萃取浮动溶剂固化——原子吸收光谱法测定环境水体样品中的重金属

采用了十一醇为萃取剂,吡咯烷二硫代甲酸铵(APDC)为络合剂的分散液液微萃取浮动溶剂固化-石墨炉原子吸收光谱法(DLLME-SFO-GFAAS)测定水体样品中痕量金属离子的分析方法,对实验条件进行了优化,改进了传统萃取方法中试剂用量大、手续繁琐、易交叉感染等不足。同时对方法测量检出限及回收率进行试验,结果表明在优化的实验条件下铜、镉、铅的检出限分别0.03μg/L、0.03μg/L和0.01μg/L,加标回收率在95.3%--102.4%,方法准确、可靠。     

高纯氢中痕量杂质变温浓缩装置及方法

为解决高纯氢中痕量杂质的分析问题,对变温浓缩样品气前处理装置进行探讨,介绍了装置的工作原理、气路设计和部件选择等;研究装置的浓缩方法,确定样品气流量、浓缩体积、脱附温度等操作条件,并对方法的可靠性做了评价。     

Emission spectrographic technique for the quantitative determination of trace elements in granitic rocks

An emission spectrographic technique was developed to estimate 16 trace elements in some samples of Egyptian granite. The detection limits were: 0·1 ppm for Pb, Ba, Mo, Cu, Cr, Yb and Ni, 0·3 ppm for Sn, Ga and Be, 1 ppm for Co, Sc and V, 3 ppm for Bi and Y and 10 ppm for La. The relative deviation of the two-thirds limits ranges between ± 1·5 and ±24·7.     

食品中磷的测定方法的改进

用定磷试剂代替国标方法中的钼酸铵、对苯二酚和亚硫酸钠溶液与待测液反应生成磷钼蓝进行比色分析测定磷含量,避免了有毒试剂对苯二酚对试验人员的危害及对环境的污染。试验结果表明,改进法提高了测定灵敏度,扩大了被测液的酸度范围,方法的检出限为1.3μg,回收率为96.8%～99.4%,测定结果与国标方法的测定结果比较无显著统计学差别,该方法可用于食品中磷的测定。     

Importance of nanoparticle size in colorimetric and SERS-based multimodal trace detection of Ni(II) ions with functional gold nanoparticles

Colorimetric detection of analytes using gold nanoparticles along with surface-enhanced Raman spectroscopy (SERS) are areas of intense research activity since they both offer sensing of very low concentrations of target species. Multimodal detection promotes the simultaneous detection of a sample by a combination of different techniques; consequently, surface chemistry design in the development of multimodal nanosensors is important for rapid and sensitive evaluation of the analytes by diverse analytical methods. Herein it is shown that nanoparticle size plays an important role in the design of functional nanoparticles for colorimetric and SERS-based sensing applications, allowing controlled nanoparticle assembly and tunable sensor response. The design and preparation of robust nanoparticle systems and their assembly is reported for trace detection of Ni(II) ions as a model system in an aqueous solution. The combination of covalently attached nitrilotriacetic acid moieties along with the L-carnosine dipeptide on the nanoparticle surface represents a highly sensitive platform for rapid and selective detection of Ni(II) ions. This systematic study demonstrates that significantly lower detection limits can be achieved by finely tuning the assembly of gold nanoparticles of different core sizes. The results clearly demonstrate the feasibility and usefulness of a multimodal approach.     

氧弹燃烧法测定聚乙烯和聚丙烯材料中的微量卤素

试样通过氧弹燃烧的方法,采用离子色谱仪测定卤素含量,准确可靠地定量聚乙烯和聚丙烯类材料中的微量卤素。4个元素的标准曲线线性相关性良好,相关系数为0．99997、0．99969、0．99940和0．99954,各6次的重复进样结果表明此法测定F-、CI-、Br和l-的相对标准偏差均〈5％。     

Explicit determination of element stiffness matrices in the hybrid stress method

The hybrid stress method has demonstrated many improvements over conventional displacement-based formulations. A main detraction from the method, however, has been the higher computatational cost in forming element stiffness coefficients due to matrix inversions and manipulations as required by the technique. By utilizing permissible field transformations of initially assumed stresses, a spanning set of orthonormalized stress modes can be generated which simplify the matrix equations and allow explicit expressions for element stiffness coefficients to be derived. The developed methodology is demonstrated using several selected 2-D quadrilateral and 3-D hexahedral elements.     

Development of a cloud point extraction-spectrofluorimetric method for trace copper(II) determination in water samples and parenteral solutions

A simple and efficient cloud point extraction-spectrofluorimetric method for the determination of copper(II) in different samples has been proposed. The procedure is based on the oxidation of thiamine with copper(II) to form highly fluorescent thiochrome, its extraction to Triton X-114 micelles and spectrofluorimetric determination. The variables affecting the analytical performance were studied and optimized. The calibration graphs using the preconcentration system for copper were linear over the range 1.0-250 ng ml-1 with limit of detection of 0.29 ng ml-1. Relative standard deviation for five replicate determinations of copper at 100 ng ml-1 concentration level was 2.12%. Average recoveries between 94 and 105% were obtained for spiked samples. The method has been applied to water samples and parenteral solutions and the amounts of copper found are very similar to those obtained by a standard method.     

Towards an ultrasensitive method for the determination of metal impurities in carbon nanotubes

Residual catalyst metal nanoparticles remain one of the major obstructions in the utilization of carbon nanotubes (CNTs) in many areas owing to their ability to participate in redox chemistry of biomarkers. Presented here is a comparative study of several techniques for quality control of carbon nanotubes in terms of metallic impurities, namely magnetic susceptibility, electron paramagnetic resonance, energy-dispersive X-ray spectrometry, X-ray photoelectron spectroscopy, and thermogravimetric analysis. It is found that the dc magnetic susceptibility is the most sensitive method such that the difference between two CNT samples that underwent slightly different treatments can be detected, whereas the two samples are indistinguishable by other techniques. Therefore, it is suggested that the most accurate statistical method for quality control of carbon nanotubes is dc magnetic susceptibility, which allows the detection of traces of magnetic metal impurities embedded in purified carbon nanotubes, whereas other methods may provide false "impurity-free" information.     

4-氨基安替比林直接光度法测定废水中挥发酚的改进

本文对废水中挥发酚的测定方法进行了补充和改进,缩短了废水中挥发酚分析测试时间,提高了工作效率。并就分析测试中需重点注意的环节方面进行探讨与分析。