基体改进效应石墨炉原子吸收测定环境和生物样品中镓、铟和铊

本文研究了环境、地质及生物样品中镓、铟、铊的测定条件,试验了金属盐类、有机化合物及金属碳化物涂层石墨管对测定镓、铟、铊的基体改进作用,确定了每一个待测元素的最佳基体改进剂体系。实验表明:镍的存在可使镓的允许灰化温度由900℃增至1200℃,灵敏度提高6倍,钯能使水溶液里的铟的允许灰化温度由800℃增至1200℃,灵敏度增加了3倍多,并能使有机萃取液中的锢的允许灰化温度由小于400℃增至1000℃,灵敏度提高11倍,从而可直接测定有机萃取液中的锢。然而,仅有镍或把基体改进剂存在时,高氯酸及其盐将严重干扰实际样品中镶、锢、蛇的准确测定。为此,比较了各种试剂在镍或把存在下的消除干扰的能力,得出一定量的硫酸按或抗坏血酸,可使镓、铟、铊测定时的高氯酸的最大允许浓度由0.0001-0.0003M增至0.3-1.0M,高氯酸盐的允许浓度为0.01M,从而有效地消除了基体干扰。基于这些研究,提出了以镍一硫酸按和钯一抗坏血酸作基体改进剂直接测定环境、地质和生物样品中痕量稼、锢和铊,以钯作基体改进剂结合NH₄I-MIBK萃取测定各种样品中痕量铟的方法,并成功地用于各实际样品的测定。工作中推测了镓、铟的原子化机理和镍、钯改进剂的作用;探讨了高氯酸(盐)的干扰机理和硫酸按,抗坏血酸的消除干扰的原因。     

基体改进效应石墨炉原子吸收测定环境和生物样品中镓、铟和铊

本文研究了环境、地质及生物样品中镓、铟、铊的测定条件,试验了各种金属盐类、有机化合物及各种金属碳化物涂层石墨管对测定镓、铟、铊的基体改进作用,确定了每一个待测元素的最佳基体改进剂体系。实验表明:镍的存在可使镓的允许灰化温度由900℃增至1200℃,灵敏度提高6倍。     

石墨炉原子吸收法直接测定全血中镉和铅

直接测定人体血镉和血铅较为困难。本文介绍用铂作基体改进剂以提高镉、铅的灰化温度,在灰化阶段除去产生高背景吸收的蛋白,而不发生镉、铅的挥发损失。实现了不需消化样品、络合提取等复杂的化学前处理,用石墨炉原子吸收法和校正曲线直接测定。同时应用衬钽技术,大大延长了石墨管的使用寿命。     

石墨炉原子吸收测定硅酸盐岩石样品中铍时各种石墨管的应用

石墨炉原子吸收测定铍,由于基体的影响,常常采用标准加入法,预先分离基体和在标准溶液中加入基体元素等方法,这些方法比较费时,给分析带来许多不便。近年来,由于等温平台石墨炉和加基体改进剂等方法,对消除基体元素的干扰比较成功,因此被人们普遍采用。本工作不用平台,不加基体改进剂,而采用最大功率加热方式,分别利用热解镀层石墨管(简称PGT),普通石墨管(简称GGT)和衬钽管(简称TaT),直接分析岩石样品中     

石墨炉原子吸收光谱法测定痕量钒的研究

本文采用石记原子吸收光谱对钒吸收线的特征，普通石墨管和热解石墨管中钒的原子化行为，灰化和原子化条件，基体效应等进行了研究，综合应用基体改进剂，光控升温和解石墨管技术，提高了电热原子吸收测定钒的灵敏度，特征质量为２４ｐｇ／０．００４４Ａ。     

石墨炉原子吸收测定岩石矿物中痕量镓

镓是稀有分散元素,其化合物容易挥发。用石墨炉原子吸收测定镓的文献报道较少。岩石矿物中的痕量镓常使用有机试剂萃取分离,比色法测定,其方法的灵敏度较低。本文通过实验,提出:在盐酸-碘化钾-抗坏血酸介质中,用甲基异丁基甲酮(MIBK)萃取镓,以镍作基体改进剂,用自制的简易石墨炉平台测定。本方法简单,灵敏度高,适应于地质样品及水质样品中痕量镓的测定。灵敏度为     

石墨炉原子吸收光谱法测定氧化钐和氧化钆中的铕

采用衬钽片的石墨管,以石墨炉原子吸收光谱法测定了氧化钐和氧化钆中的铕。探讨了盐酸浓度,基体钐和针对铕测定的影响;考察了方法的灵敏度和精密度;建立了灵敏准确易于掌握的分析方法。 本方法不需要预先分离基体,样品经溶解后即可直接进行分析。     

石墨炉原子吸收法直接测定高温合金中硅

研究了混合基体改进剂，灰北、原子化温度以及共存元素的干扰，采用镧和钙作混合基体改进剂后，硅的灵敏度提高，抗干扰能力增强，可以用石墨炉原子吸收直接测定高温合多中硅。方法特征量为０．２ｎｇ，检出限为２．３μｇ／ｇ，对于含硅量为４００μｇ／ｇ左右的合金样品，相对标准偏差为５％左右，回收率在９０％－１１０％之间。     

电热原子吸收光谱法测定微量镱

随着电热原子吸收光谱法的发展,采用热解石墨涂层管测定稀土元素,灵敏度较火焰法有所提高,但由于在高温下稀土元素易与石墨反应生成碳化物,存在记忆效应,灵敏度、精度及抗干扰能力仍较差。测定某些实际样品如高纯稀土氧化物中的微量Yb尚存在一定困难。藤野治等采用电热原子吸收光谱法测定磷酸盐矿石中的Yb,因基体干扰严重,仍需要事先进行化学分离,难以推广。近年来,文献报导采用衬钽片的石墨管、衬钨钽的热解石墨管测定微量稀土元素,性能有了改进。但均未用于含微量Yb的实际样品分析。本     

基体改进剂石墨炉原子吸收光谱直接测定饮料中的砷、铅、铜的研究

饮料是食品卫生监督检验的常测样品,饮料中的砷、铅、铜的含量是必测的指标。长期以来样品均采用酸式湿消化或碱式干灰化处理,分别用化学法测定,分析速度慢,方法的灵敏度也较低。近年来出现的基体改进剂石墨炉原子吸收光谱直接测定食品中铅和铜的方法,使分析速度和灵敏度都有了很大提高。但在食品中直接测砷却遇到很大的困难,砷是允许灰化温度最低的元素,在食品样品中,由于有大量有机物的作用,使它更容易损     

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.     

Determination of the rare earths, yttrium and scandium in silicate rocks and four new geological reference materials by electrothermal atomization from graphite and tantalum surfaces

An improved graphite furnace atomic-absorption method has been developed for the determination of Sc, Y and the rare-earth elements in silicate rocks and related materials. The method, which involves the separation of the lanthanides by ion-exchange followed by their determination by electrothermal atomization, with use of an automatic sampling device, is more rapid than a previous method based on separation by co-precipitation with calcium oxalate and hydrous ferric oxide followed by normal injection of the solution into the furnace. Greater sensitivity (~ 10-40-fold) for La, Ce, Pr, Gd, Tb and Lu is also achieved by using a tantalum foil-lined graphite furnace instead of a pyrolytically-coated furnace. Results obtained for five international reference rock samples, NIM-G, SCo-1, MAG-1, SDC-1 and BHVO-1, are compared with those obtained previously by the oxalate-hydrous oxide co-precipitation method and with other published values. Results are given for four new Canadian iron-formation reference materials, FeR-1 to FeR-4.     

Investigation of phosphorus atomization using high-resolution continuum source electrothermal atomic absorption spectrometry

The atomization of phosphorus in electrothermal atomic absorption spectrometry has been investigated using a high-resolution continuum source atomic absorption spectrometer and atomization from a graphite platform as well as from a tantalum boat inserted in a graphite tube. A two-step atomization mechanism is proposed for phosphorus, where the first step is a thermal dissociation, resulting in a fast atomization signal early in the atomization stage, and the second step is a slow release of phosphorus atoms from the graphite tube surface following the adsorption of molecular phosphorus at active sites of the graphite surface. Depending on experimental conditions only one of the mechanisms or both might be active. In the absence of a modifier and with atomization from a graphite or tantalum platform the second mechanism appears to be dominant, whereas in the presence of sodium fluoride as a modifier both mechanisms are observed. Intercalation of phosphorus into the graphite platform in the condensed phase has also been observed; this phosphorus, however, appears to be permanently trapped in the structure of the graphite and does not contribute to the absorption signal.     

Determination of Beryllium in Natural Waters Using Atomic Absorption Spectrometry With Tantalum-Coated Graphite Tube

Abstract

In the present paper a method for direct determination of beryllium in natural waters, especially in surface waters, using atomic absorption spectrometry with graphite furnace is described. Two procedures are compared, using an ordinary graphite tube and matrix modifier Mg(NO₃)₂, and using a tantalum coated tube without any modifier added. The detection limit (3[sgrave]) of the proposed method using the tantalum-coated tube is proved to be 0.02 μgBe/1. With the developed method the Be content in natural water samples collected from highly polluted and reference regions of Bohemia were determined. A certified reference material (IAEA/W-4) was also analysed to prove the accuracy of proposed method.     

石墨炉原子吸收光谱法测定高温合金中镓

研究了普通石墨管、平台石墨管和涂钼普通石墨管对镓的测定性能.得出涂钼普通石墨管对镓的测定灵敏度和重现性均好于其他石墨管.从而建立了一种更为满意的石墨炉原子吸收测定高温合金中镓的新方法.     

石墨炉原子吸收法测定渗透水中的铍

本文用塞曼效应石墨炉原子吸收法测定铍，以抗坏血酸作基体改进剂，使测定铍的灵敏度提高，并且提高了灰化温度和降低原子化温度，增强抗干扰能力。利用抗坏血酸的增感作用直接测定了渗透水和水系沉积物中的痕量铍。     

石墨炉原子吸收光谱法测定碘化铯晶体中铊

采用平台石墨炉原子吸收光谱法测定了碘化铯晶体中铊。研究了碘化铯对钯－硝酸镁基本改进剂中铊吸光度影响,用预混合钯－硝酸镁和样品溶液,由于在碘化物溶液中易析出金属钯而使测定结果降低。用样品溶液和基体改进剂分别加入到石墨炉中的标准加入法可得到满意的结果。     

Some observations on the atomic absorption spectrometry of gallium with electrothermal atomizers

Signal strength can be doubled in normal graphite furnaces compared to pyrolytically coated ones, thus proving the essential role of carbon in the atomization of gallium. Platform vaporization enhances both peak height and area signals. The use of ascorbic acid as matrix modifier improves sensitivity considerably, with enhancements being more pronounced in pyrolytically coated furnaces.