钨丝在原子吸收光谱分析中的应用

随着原子化器和检测器的小型化,钨丝原子吸收光谱分析仪在便携式分析仪器方面显示了很大的潜力.本文主要评述了近年来钨丝在电热原子吸收光谱分析中的应用,引用文献49篇.     

电沉积-钨丝电热原子吸收光谱法测定地质样品中痕量金

以市售幻灯投仪卤钨灯泡钨丝为原子化器的钨丝电热原子吸收光谱分析仪(TC-AAS),功率小、仪器成本低[1,2],如用微型CCD光谱仪作检测系统,可以实现原子吸收光谱仪的小型化,甚至可用于野外现场分析[3,4].     

电沉积-钨丝电热原子吸收光谱法测定水样中的铅

研制了一种便携式钨丝电热原子吸收光谱分析装置,其主要包括:钨丝电热原子化器、多道微型CCD光谱仪、仪器电源系统以及控制系统。并将电沉积分离富集技术与该钨丝电热原子吸收光谱分析仪器结合,完成环境水样中铅的现场分析。并对铅的电沉积条件作了研究,最佳电沉积电位为负650 mV(vs.SCE),方法检出限:0.20μg/L,线性范围:1~15μg/L,对4μg/L Pb标准溶液10次重复测试,RSD为4.4%。     

壳聚糖富集火焰原子吸收法测定水中痕量铜

采用壳聚糖修饰钨丝基质螺旋卷，直接浸入含有痕量铜的pH5．0的Brltton-Robinson缓冲溶液中，经电磁搅拌富集一定时间后，将其转移至空气／乙炔火焰燃烧器上，利用火焰原子吸收光谱法简便快速测定水中痕量铜。方法的线性范围为2—75μg／L；检出限为0．98μg／L。同一支钨丝螺旋卷重复涂敷壳聚糖富集Cu，RSD(n=6)为2．7％。     

钨丝电沉积石墨炉原子吸收光谱法测定食品中不稳定态铅

研究了钨丝电沉积石墨炉原子吸收光谱法测定不稳定态铅的条件。结果表明该方法的灵敏度比常规ＣＦＡＡＳ法提高８０倍，检出限为０．０１μｇ．Ｌ－１；变异系数４．５％，在０－２．５μｇ·Ｌ－１范围内线性关系好，抗干扰强。测定了食品中不稳定态铅。     

钨丝电热原子吸收光谱分析法测定痕量锌

蒸馏水中的锌与吡咯烷二硫代氨基甲酸铵(APDC)形成的络合物用CCl4萃取后,弃去有机相,水相用作配制锌标准溶液和制备样品溶液,从而解决了用钨丝电热原子吸收光谱法测锌时空白值太高而难以进行实际样品分析的问题.考察了影响萃取和钨丝电热原子吸收测定的各种实验条件.在进样10 μL样品溶液时,本方法的定量下限为5 μg/L.测定了3个国家标准物质(大米、人发和水系沉积物)中的锌含量,结果与推荐值一致.     

钨丝电热蒸发-氩/氢火焰原子吸收光谱分析方法

基于钨丝电热蒸发设备,建立了一种全新的钨丝电热蒸发-氩/氢火焰串联原子吸收光谱系统.研究了系统抗酸、抗盐能力,结果表明:Na<'+>和Ca<'2+>质量浓度小于400 mg/L、Mg<'2+>质量浓度小于1500 mg/L时不干扰测定.在优化的仪器条件下:Pb、Cd、Au和Ag的检出限分别为:0.016、0.0005、...     

原子吸收光谱法测定铅的进展

对近年来国内原子吸收光谱法测定铅的进展进行了评述，内容包括火焰原子吸收光谱法、石墨炉原子吸收光谱法和氢化物发生原子吸收光谱法。     

电解预浓缩技术在原子吸收分光光度分析中的应用

本文介绍了电解预浓缩技术的基本装置和各种工作电极材料,重点评述钨丝工作电极在火焰和无火焰原子吸收分析中的应用及其利弊,指出采用电解后的钨丝直接作原子化器可以弥补仪器设备的不足。最后表列出该技术在原子吸收分析中的应用现状。     

电沉积分离富集钨丝电热原子吸收测定微量钯

本文介绍一种电热原子吸收光谱分析测定微量钯的新方法。将溶液中微量钯电还原沉积到钨丝表面,该钨丝再通以一定功率电流使其表面沉积的金属钯蒸发原子化并测量吸光度。确定了各实验参数最佳值,讨论了各种影响因素。电沉积时间(?)秒时,检出限为1.49ng/mL,相对标准偏差为5.18％,钯含量在0-30ng/mL范围内与吸光度呈线(?)关系。方法可用于若矿、催化剂及阳极泥等试样的发析,用管理样进行了分析结果对照,准确度和精密度均较好。     

原子吸收光谱法在烟草行业中的应用进展

对1961～2011年间3种类型的原子吸收光谱法,包括火焰原子吸收光谱法、石墨炉原子吸收光谱法和蒸气发生原子吸收光谱法在烟草行业中的应用进行了综述(引用文献63篇)。     

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。     

Atomic absorption with ultracold atoms

Recent advances in laser-atom cooling techniques and diode-laser technology now allow one to conduct an idealised atomic absorption experiment comprising a sample of ultracold, quasi-stationary absorbing atoms and a source of near-monochromatic resonant light. Under such conditions, the atomic absorption coefficient at line centre is independent of the oscillator strength of the atomic resonance line. This offers the prospect of ‘oscillator-strength-free’ atomic absorption spectroscopy in which the absorption signal is equally large for both strong and weak (closed) transitions of the same wavelength and in which absolute atomic absorption could be performed without knowledge of the oscillator strength. Moreover, the resolution and sensitivity for a given atom density are greatly enhanced, typically by approximately three orders of magnitude (and even more for weak transitions), compared with conventional flame or graphite-furnace atomic absorption. We describe an atomic absorption experiment based on samples of ultracold, laser-cooled caesium atoms and a narrow-bandwidth diode laser source that approximates the idealised conditions for oscillator-strength-free atomic absorption. The absorption measurements are used to determine the number density and temperature (approx. 6 μK) of the sample of ultracold atoms. Some of the technical obstacles that would have to be overcome before samples of ultracold atoms and diode laser sources could be used in analytical atomic absorption spectroscopy are discussed.     

食品中无机盐检测方法研究进展

介绍了食品中无机盐前处理和检测技术研究进展,主要阐述了包括火焰原子吸收光谱法、石墨炉原子吸收光谱法、电感耦合等离子体原子发射光谱法、原子荧光光谱法、X射线荧光光谱法及联用等技术在近年来的应用,并对以后的发展方向进行了展望。     

The Determination of Silicon in low Alloy Steels by Atomic Fluorescence Spectroscopy in A Separated Nitrous Oxide-Acetylene Flame

Abstract

An atomic fluorescence spectroscopic method is described for the assay of silicon in low alloy steels. The method reported is more sensitive than the corresponding atomic absorption method, the detection limit being 0.7 ppm at 351.6 nm compared to 4 ppm for atomic absorption at the same wavelength.     

Comparison of electrothermal atomic absorption spectrometry of the metal content of sewage sludge with flame atomic absorption spectrometry in conjunction with different pretreatment methods

Determination of the metal content of sewage sludges is of increasing importance in order to assess the suitability of the sludge for disposal to agricultural land. The methods currently used for the determination of cadmium, chromium, copper, nickel, lead and zinc are time-consuming. A rapid electrothermal atomic absorption procedure with homogenization as the only pretreatment is compared with wet and dry pretreatment methods followed by flame atomic absorption spectrometry, in a statistically designed experiment. The precision of the rapid electrothermal atomic absorption procedure compares well with flame atomic absorption in conjunction with all pretreatment methods used. Time saved by the use of this method is substantial; the procedure could be used advantageously for routine analysis.     

Determination of cobalt in biological samples by line-source and high-resolution continuum source graphite furnace atomic absorption spectrometry using solid sampling or alkaline treatment

Two procedures for the determination of Co in biological samples by graphite furnace atomic absorption spectrometry (GF AAS) were compared: solid sampling (SS) and alkaline treatment with tetramethylammonium hydroxide (TMAH) using two different instruments for the investigation: a conventional line-source (LS) atomic absorption spectrometer and a prototype high-resolution continuum source atomic absorption spectrometer. For the direct introduction of the solid samples, certified reference materials (CRM) were ground to a particle size ≤50 μm. Alkaline treatment was carried out by placing about 250 mg of the sample in polypropylene flasks, adding 2 mL of 25% m/v tetramethylammonium hydroxide and de-ionized water. Due to its unique capacity of providing a 3-D spectral plot, a high-resolution continuum source (HR-CS) graphite furnace atomic absorption spectrometry was used as a tool to evaluate potential spectral interferences, including background absorption for both sample introduction procedures, revealing that a continuous background preceded the atomic signal for pyrolysis temperatures lower than 700 °C. Molecular absorption bands with pronounced rotational fine structure appeared for atomization temperatures >1800 °C probably as a consequence of the formation of PO. After optimization had been carried out using high resolution continuum source atomic absorption spectrometry, the optimized conditions were adopted also for line-source atomic absorption spectrometry. Six biological certified reference materials were analyzed, with calibration against aqueous standards, resulting in agreement with the certified values (according to the t-test for a 95% confidence level) and in detection limits as low as 5 ng g⁻¹.     

Some causes of bending of analytical curves in atomic absorption spectroscopy

Some factors affecting the shape of analytical curves in atomic absorption spectroscopy are considered and the influence of the emission and absorption line profiles is discussed in detail. An empirical equation expressing the analytical curves for different ratios of emission line width to absorption line width is given. The possible influence of resonance line broadening and resonance line shift in atomic absorption flame photometry is also discussed.     

Investigation of chemical modifiers for phosphorus in a graphite furnace using high-resolution continuum source atomic absorption spectrometry

Phosphorus is not one of the elements that are typically determined by atomic absorption spectrometry, but this technique nevertheless offers several advantages that make it attractive, such as the relatively great freedom from interferences. As the main resonance lines for phosphorus are in the vacuum–ultraviolet, inaccessible by conventional atomic absorption spectrometry equipment, L´vov and Khartsyzov proposed to use the non-resonance doublet at 213.5 / 213.6 nm. Later it turned out that with conventional equipment it is necessary to use a chemical modifier in order to get reasonable sensitivity, and lanthanum was the first one suggested for that purpose. In the following years more than 30 modifiers have been proposed for the determination of this element, and there is no consensus about the best one. In this work high-resolution continuum source atomic absorption spectrometry has been used to investigate the determination of phosphorus without a modifier and with the addition of selected modifiers of very different nature, including the originally recommended lanthanum modifier, several palladium-based modifiers and sodium fluoride. As high-resolution continuum source atomic absorption spectrometry is revealing the spectral environment of the analytical line at high resolution, it became obvious that without the addition of a modifier essentially no atomic phosphorus is formed, even at 2700 °C. The absorption measured with line source atomic absorption spectrometry in this case is due to the PO molecule, the spectrum of which is overlapping with the atomic line. Palladium, with or without the addition of calcium or ascorbic acid, was found to be the only modifier to produce almost exclusively atomic phosphorus. Lanthanum and particularly sodium fluoride produced a mixture of P and PO, depending on the atomization temperature. This fact can explain at least some of the discrepancies found in the literature and some of the phenomena observed in the determination of phosphorus using line source atomic absorption spectrometry.     

X-ray absorption in atomic Cd in the K-edge region

The X-ray absorption in the K-edge region is measured on Cd vapor in a sealed high-temperature cell. The absorption spectrum, free of structural signal, represents atomic absorption of the element, with fingerprints of multielectron excitations visible after natural-width deconvolution. Absolute values of the atomic photoabsorption coefficient are obtained from renormalization with Cd foil data far from the edge. Possible sources of systematic error in synchrotron radiation measurement of absolute absorption are discussed.