Factors Affecting Selenium Atomization Efficiency in Graphite Furnace Atomic Absorption

Abstract

The effect of graphite furnace surface treatment, and the addition of “matrix modifiers” such as nickel or lanthanum on the observed selenium atomization siqnal in electrotherval atomic absorption analysis has been investiqated. The results indicate that the removal of signal depression caused by the addition of metal solution to analyte solution is not simply a devolatilization of the selenium. The effect appears to be a modification of the graphite surface which leads to more efficient atom formation. The role of the surface was investigated monitoring the atomic absorption signal generated from graphite furnaces which were untreated, pyrolytic graphite-coated, zirconium-or tantalum-coated, and metal-coated followed by pyrolytic graphite coating. The dependence of the analyte signal on the concentration of added metal was investigated for these surfaces. The optimum results obtained were the metal-coated/pyrolytic graphite-coated cuvettes. These cuvettes showed reduced effect of “matrix modifier,” suggesting that the surface treatment can replace the “matrix modifer,” Surface chemistry consistent with the atomic absorption observations and surface analysis data is presented.     

Determination of Barium in Bottled Drinking Water by Graphite Furnace Atomic Absorption Spectrometry

Abstract

In relation to the wide environmental spread of barium and to its cardiovascular effects, barium levels were determined by graphite furnace atomic absorption spectrometry in 60 different brands of bottled water marketed in Italy.

Matrix interferences were investigated in order to evaluate the use of an analytical calibration function rather than the much more time consuming addition technique.

The barium content ranged from limit of detection C_L (7.0 μg/l) up to 660 μg/l, the median value being 80 μg/l, while the recovery tests varied between 90 and 110 % and the precision of the method (s_yx) was 2.5 %.     

Spectrometry: Speciation of Parts PER Billion of Metal Ions Using Silica and C18-Bonded Silica Columns and Graphite Furnace Atomic Absorption Spectrometry

Abstract

It is demonstrated that silica gel columns will quantitatively adsorb free Cu²⁺ and Pb²⁺ ions at pH > 8. These are eluted with 0.1 M HNO₃ but not with methanol. Negatively charged EDTA chelates are not adsorbed. Neutral APDC chelates are partially adsorbed on silica columns, but are quantitatively adsorbed on C18-bonded columns, and are eluted with methanol. The metal ions are partially adsorbed on C18-bonded columns, due to residual silanol groups. A microcolumn (1 mm i.d., 5 cm length) manifold system is described for automatic delivery of eluant (0.12 ml) to a heated atomic absorption graphite atomizer, using either methanol or 0.1 M HNO₃ in methanol eluant, allowing speciation and measurement of parts per billion of metals. These studies demonstrate that by using a mixed column or sequential columns of silica gel and C18-bonded silica, cationic and neutral metal species could be adsorbed, followed by sequential elution and measurement using methanol and then 0.1 M HNO. Negatively charged species could be measured directly in the sample eluant or obtained by difference from a total metal measurement.     

Indirect Atomic Absorption Spectrometric (AAS) Determination of Atenolol

Abstract

The Cu(II)-atenolol complex was prepared, and characterized by elemental analysis and spectroscopic techniques (via. IR, electronic and EPR spectra). The spectral results obtained indicate tetrahedral geometry around the Cu(II) ion. An indirect atomic absorption spectrometric method was undertaken to estimate atenolol in pharmaceutical preparations, based on its reaction with Cu²⁺ in alkaline medium. The method is simple, rapid, accurate and sensitive.     

石墨炉原子吸收光谱法测定生活饮用水中砷的方法优化

建立了石墨炉原子吸收光谱(GFAAS)法测定生活饮用水中砷的方法。升压放电空心阴极灯的使用,降低了基线噪声水平和检出限。对温度程序、化学基体改进剂和热稳定剂进行了优化并用于GFAAS测定砷,无需进行初步处理。研究结果显示,线性方程为y=0.005 62x+0.000 04,相关系数R为0.998 3,样品体积为16μL时的检出限为0.26μg/L。加标回收率为98.1%～99.2%,相对标准偏差5%。取实际饮用水样验证了其适用性。     

石墨炉原子吸收光谱法测定生活饮用水中砷的方法优化

建立了石墨炉原子吸收光谱(GFAAS)法测定生活饮用水中砷的方法。升压放电空心阴极灯的使用,降低了基线噪声水平和检出限。对温度程序、化学基体改进剂和热稳定剂进行了优化并用于GFAAS测定砷,无需进行初步处理。研究结果显示,线性方程为y=0.005 62x+0.000 04,相关系数R为0.998 3,样品体积为16μL时的检出限为0.26μg/L。加标回收率为98.1%～99.2%,相对标准偏差<5%。取实际饮用水样验证了其适用性。     

The Determination of Yttrium in High Temperature Refractory Oxides by Atomic Absorption Spectroscopy

Abstract

A rapid method is described for determining yttrium in refractory zirconia using atomic absorption spectroscopy. The sample is fused with a mixture of LiBO₂ and H₃BO₃, and the melt is dissolved in hot dilute HClO₄. A flame buffer consisting of potassium and EDTA is employed to effect maximum absorbance. The compositions of the standard solutions are matched as closely as possible to the samples. The yttrium absorbance is measured at 410.2 nm using a stoichiometric NS₂O + C₂H₂ flame. Sulfate, phosphate, calcium, and magnesium do not interfere. Silica can be removed by fuming with HF before the fusion. Recovery studies show that the procedure is sufficiently accurate to be used for the routine determination of yttrium in samples containing from 2 to 18% Y₂O₃.     

Indirect Atomic Absorption Spectrometric Determination of Ammonia,Thiosulfate and Cyanide in an Unsegmented Flow System

Abstract

A flow injection analysis method (FIA), has been developed for the determination of cyanide, thiosulfate and ammonia by atomic absorption spectrometry (AAS). Aqueous solution of the analyte was injected into an on-line column containing glass beads and packed with silver chloride and deionized water was used as the carrier. The analyte dissolves the silver chloride and the dissolved silver complex is introduced to the nebulizer of the AAS. This method has proved to be sensitive, simple and precise. Detection limits of 1.0 × 10^?7 M, 5.0×10^?7 M and 5.0x10^?6M were obtained for thiosulfate, cyanide and ammonia, respectively. The precision of the technique was 2.0%, 2.4% and 1.4% in case of thiosulfate, cyanide and ammonia, respectively. The effects of flow rate and sample volume on the FIA/AAS signals are presented.     

Indirect Determination of Lidocaine by Atomic Absorption Spectrophotometry

Abstract

A new procedure for determining lidocaine chlorhydrate is described. The method consists of extracting an ion pair composed of Lidocaine and the inorganic complex Co(SCN)₄ ^2- into an organic solvent (1, 2 dichloroethane), then measure the Co in the organic phase by A.A.S. at 240.7 mm. Optimal experimental conditions concerning pH, Co(SCN)₄ ^?2 concentration, shaking time, phase ratio, number of extractions and linear range for calibration are studied. The method has a standard deviation of 10^?2. Two pharmaceutical preparations containing lidocaine, have been analyzed with very good results.     

巯基棉分离富集-石墨炉原子吸收法测定痕量铟的研究

研究了巯基棉(SCF)富集痕量In(Ⅲ)的条件,并用石墨炉原子吸收光谱(GFAAS)法测定痕量In(Ⅲ)。结果表明,在pH=4.0时,巯基棉能定量富集痕量In(Ⅲ),其饱和吸附量为181μg/g。吸附的In(Ⅲ)可被0.8 mol/L的HNO3定量洗脱。本法用于人工合成铝基、锌基样品和锌精矿中痕量In(Ⅲ)的富集和测定,回收率为92.8%~100.6%。     

Selenium Determination in Serum by Graphite Furnace Atomic Absorption Spectrometry

Selenium concentration in serum has been proposed as the most valuable indicator of human selenium status. In this work, the concentration of selenium in serum is measured by GFAAS using longitudinal Zeeman-effect background correction, a highly sensitive technique that can be used to determine selenium at sub-ppb level. Standard reference materials are analyzed to verify the accuracy and precision of this technique. The direct method proposed in this study is used for the determination of selenium in human serum collected from healthy people of 19–25 years and women of 21–34 years in the First trimester of pregnancy. The method developed in this study, which can quickly and accurately measure serum selenium, is suitable for applications in clinical diagnosis or biological monitoring.     

石墨炉原子吸收光谱中海水的背景吸收研究

由于海水的成分复杂,含盐量高,给用石墨炉直接测定其中的痕量杂质带来许多困难^[1]。Sturgeon等用预先分离的方法来克服干扰^[2]。为了进行直接测定,研究海水背景吸收的来源、特点和消除方法是重要的。海水背景吸收的波长特性和在石墨管内蒸发行为的研究表明,海水的背景吸收主要来自氯化钠。时间特性的研究表明,背景吸收的时间分布及背景峰高与原子化阶段的加热方式和原子化温度有关。作者还研究了基体改进。剂和其它减小背景吸收的方法。     

间接原子吸收法测定苯并三氮唑

乙酸钠介质中 ,加入过量的铜 (Ⅱ )与苯并三氮唑生成沉淀 ,用火焰原子吸收法测定上清液中剩余的铜(Ⅱ ) ,工作曲线法测定了工业合成样品及内燃机冷却水中的苯并三氮唑。该方法测定苯并三氮唑线性范围为1 2mg/L～ 30mg/L ,回收率 (n =5)为 98.9～ 1 0 1 .0 %。文中还测定了难溶化合物的溶解度、溶度积和化合物的组成比。     

石墨炉原子吸收光谱法测定转基因棉籽中的铅镉铜铬

本文探讨了干法灰化与湿法消解-石墨炉原子吸收光谱法测定转基因与非转基因棉籽中重金属元素铅、镉、铜和铬的方法,比较了两种预处理方法对测定结果的影响.结果表明:两种方法均能满足分析测定的需要.将分析方法应用于转基因与非转基因棉籽中四种重金属含量的测定,结果显示,转基因棉籽中铅和铜的含量明显低于非转基因棉籽,镉和铬的含量与非转基因棉籽相当.     

Critical Study of the Determination of Palladium by Graphite Furnace- Atomic Absorption Spectrometry

Abstract

The atomic absorption spectroscopic behaviour of palladium in a graphite furnace has been investigated. The determination is several ordes of magnitude more sensitive than the flame technique. The use of Tantalum coated tubes does not improve considerably the sensitivity but prolongs the lifetime of the furnaces.     

火焰原子吸收光谱法分析中药中锌的形态

采取正辛醇水分配体系模拟中药水煎液中锌在人体胃肠中的分配情况，用原子吸收光谱法测定了十二味中药药材及其水剪液中锌的含量，水煎液中水溶态锌、醇溶态锌的含量。实验结果表明，中药中锌的水煮溶出率较氏，中药中锌的形态与中药成分，配伍情况及作用靶位（胃肠）的酸度有关，酸度及配伍对中药中锌的溶出率及水煎液中锌的形态影响较大。     

原子吸收及原子荧光光谱分析

本文是《分析试验室》期刊定期评述中关于原子吸收光谱 (AAS)及原子荧光光谱 (AFS)分析的第 9篇综述文章。文中对 2 0 0 0年 12月～ 2 0 0 2年 11月期间我国在AAS AFS领域所取得的主要进展进行评述。内容包括概述、仪器装置、火焰原子吸收光谱法、电热原子吸收光谱法、化学蒸气发生技术以及原子荧光光谱法等。收集文献 35 8篇。     

A Study of Two Atomic Absorption Methods for the Determination of Sub-Microgram Amounts of Arsenic and Selenium

Abstract

Two atomic absorption accessory units were studied for the determination of arsenic and selenium in waters. One involves a flame mode while the other a flameless mode. Each was analyzed for requirements in speed per analyses, sample sizes required, potential interferences, coefficients of variation, and in overall ease in use.

Although the flameless mode could determine lower levels of arsenic and selenium than the flame mode, it was hampered by some severe interferences. Advantages of these accessories in their use over conventional wet chemical methods included: speed per analysis, elimination of time-consuming concentration steps, and elimination of using fragile equipment and noxious solvents.     

Indirect Determination of Bromhexine by Atomic Absorption Spectrophotometry

Abstract

A new procedure for determination of Bromohexine is described. The method consists of extracting an ion pair between the Bromhexine and the inorganic complex Co(SCN)² ₄ and measuring Co in the organic phase by AAS at 240. 7 nm. The optimal experimental conditions: pH, concentration of Co(SCN)² ₄, shaking time, phase ratio, number of extractions and the linear range of calibration are studied.

The organic phase used is 1,2-dichloroethane. The standard deviation of the method is 10^?3. The interference of foreign substances which accompany the Bromhexine in pharmaceutical preparations is studied, and the method is applied to their quantitative determination in medicines.     

Indirect Determination of Pyrrolizidine Alkaloids by Flame Atomic Absorption Spectrometry

Abstract

This paper studies the formation and extraction of ion pairs of some alkaloids derived from pyrrolizidine. The substances studied are Nemorensine, Platyphylline, Senecionine and Seneciphylline, and the ion pairs studied and extracted are formed with Bil₄. The method consists of extracting an ion pair between the organic base and the inorganic complex, the metal is measured in the organic phase (1,2 dichloroethane) by Flame AAS. The optimal experimental conditions, pH, concentration of BiI₄ ^?, shaking time, phase ratio, number of extractions, and the range of calibration are studied for these substances. The linear range in organic phase is 0.13–1.91 mg.mL^?1. The standard deviation of the method varies between 2.4–3.2%, depending on the substance analyzed. The interferences produced by various substances are studied.