浊点萃取-石墨炉原子吸收光谱法检测中成药镉残留量

建立了中成药镉残留量的浊点萃取-石墨炉原子吸收光谱法。样品先经消解,再以非离子表面活性剂浊点萃取富集消解液中的镉,石墨炉原子吸收光谱法测定镉含量。本方法检出限可达0.008ng/mL;加标回收率94.0%—108.5%;线性范围为0—10ng/mL(r=0.9995)。结果表明,采用浊点萃取可提高石墨炉原子吸收光谱法测镉的灵敏度、准确性、重复性和抗干扰能力。     

原子吸收法测定食品中微量硒

原子吸收法测定微量硒被认为是最困难的技术之一，主要因为硒是一种易挥发素。本文在前人工作基础上，以Ｐｄ＋Ｍｇ混合金属为石墨炉原子吸收法测定硒的基体改进剂，提高了灰化和原子化温度，降低了基体干扰，提高了检测灵敏度；同时还对多种金属基体改进剂和复合金属基体改进剂在石墨炉测硒时的行为进行了全面考察，并详细讨论了铁对微量硒石墨炉测定的干扰情况。     

钨丝探针电解－石墨炉原子吸收光谱法测定砷化镓中的铬

钨丝探针电解－石墨炉原子吸收光谱法测定砷化镓中的铬，灵敏度可达０．０１ｎｇ／１％吸收，相对标准偏差为３％，富集倍数达２８倍。与直接液体进样原子化方法相比，本方法具有减少环境污染、简便、灵敏度高、抗干扰能力强等优点。在研究测格的最佳条件的同时，本文还初探了铬（Ⅵ）的电解机理。     

钨丝探针电解—电墨炉原子吸收光谱法测定砷化镓中的铬

钨丝探针电解－石墨炉原子吸收光谱法测定砷化镓中的铬，灵敏度可达０．０１ｎｇ／１％吸收，相对标准偏差为３％，富集倍数达２８倍。与直接液体进样原子化方法相比，本方法具有减少环境污染，简便，灵敏度高，抗干扰能力强等优点。在研究测铬的最佳条件的同时，本文还探了铬（Ⅵ）的电解机理。     

石墨炉原子吸收光谱法测定超高纯试剂中钾和钠

本文研究了用直接进样，石墨炉原子吸收法测定超高纯试剂盐酸和硝酸中的痕量钾和钠，可省去化学处理及富集等易引致沾污的操作，采用标准加入法得到满意的结果，钾和钠的检出限分别为０．０２９ｎｇ／ｍｌ及０．００５７ｎｇ／ｍｌ。     

石墨炉原子吸收测定血和尿中锰

本文研究了用硝酸镁作为基体改进剂，石墨炉原子吸收法直接测定全血和尿血锰。方法简单，准确，快速。     

HG—100型氢化物原位富集石墨炉自动进样器

作者根据氢化物原位富集分析方法,研制了一台原子吸收用的石墨炉自动进样器。该仪器与原子吸收仪相配合,适于分析As,Se等能形成氢化物的诸元素。     

电热石墨炉原子吸收法测定贵金属——(三)岩石矿物中超痕量金的测定

本文提出了用0.5ml N-正辛基苯胺-间二甲苯萃取测定岩石矿物中超痕量金的电热石墨炉原子吸收分析方法。对萃取剂的性能、萃取金的条件、其它离子的干扰情况以及在HGA-500型石墨炉中测定金的最佳条件进行了研究。样品用盐酸过氧化氢分解后,溶液进行萃取,有机相直接测定,大量的其它离子不干扰测定,为超痕量金的定量测试提供了简便、高灵敏的方法。本法绝对灵敏度为2.0pg/1%吸收,可检测0.00005g/T金。对含金量为0.0006g/T的矿样重复溶样测定11次,其相对标准偏差为4.4%。     

固体直接进样石墨炉原子吸收法测定头发中的铜和铁

固体直接进样石墨炉原子吸收法测定人发中的痕量元素及其在人发中的纵向分布是一种有吸引力的分析方法。本文研究了测定人发中铜和铁的固体直接进样石墨炉原子吸收法,并用该法分析了日本标准人发样品中的铜和铁,所获结果与推荐值相一致。     

石墨炉原子吸收光谱法和ICP-AES测定水中镍的比较研究

通过对比石墨炉原子吸收光谱法和ICP-AES测定水中痕量镍的含量,发现ICP-AES具有直接进样、测量稳定、校准曲线线性范围宽等特点;而石墨炉原子吸收法需要较高的原子化温度,容易损坏石墨管.该方法经过t检验证明与标准方法无显著性差异,加标回收率为96.2%-105%,可以代替石墨炉原子吸收光谱法.     

一种用于表面等离子体共振传感器的纳米多孔金膜

为了打破传统的表面等离子体共振(SPR)生物传感器灵敏度不高的限制,近年来纳米材料在SPR生物传感器中的运用得到广泛的研究。但是纳米材料的制备一般都比较困难而且费用高昂,这给研究带来了困难。笔者采用化学腐蚀法制备出一种纳米多孔金膜,利用扫描电子显微镜和光谱仪等测试手段对该金膜的结构和光学性质进行了分析,并将该金膜用于SPR生物传感器实验研究。结果表明,与传统的平面金膜相比,该纳米多孔金膜具有独特的局域表面等离子体共振效应。装配有该金膜的SPR生物传感器在对生物试剂的检测中灵敏度有了一定程度的提高,且该金膜的制备方法简单,成本低廉,完全可以替代传统的平面金膜使用。     

197Au Mössbauer study of gold ores,mattes, roaster products,and gold minerals

The chemical state of gold in gold ores, mattes and roaster products has been studied by¹⁹⁷Au Mössbauer spectroscopy. Gold minerals were studied in order to provide reference data for the ore spectra.⁵⁷Fe Mössbauer spectroscopy was used to monitor the iron compounds always present in gold ores and to follow their transformations caused by smelting and roasting.     

Modeling of femtosecond laser damage threshold on the two-layer metal films

The heating processes of the single-layer gold thin film and the two-layer film assembly of gold padded with other metal (silver, copper and nickel) irradiated by femtosecond laser pulse are studied by the two-temperature model. It is found that the substrate metal can change energy transport, which is corresponding to the temperature changing process, and the thermal equilibrium time. Compared with the single-layer gold film at the same laser fluence, the two-layer film structure can change the damage threshold of the gold surface. Our results indicate that we can maximize the damage threshold of the gold film surface by altering the thickness ratio of the gold layer and the substrate layer in the two-layer film assembly.     

A197Au and57Fe mössbauer study of the roasting of refractory gold ores

The transformation of chemically bound gold into metallic gold during industrial scale roasting of an arsenical gold ore concentrate from the Fairview Mine, Eastern Transvaal, has been studied quantitatively by¹⁹⁷Au Mössbauer spectroscopy. The iron compounds in the concentrate, mainly FeAsS and FeS₂ and their transformations during roasting have been studied by⁵⁷Fe Mössbauer spectroscopy. The bound gold is found to convert into the metal in parallel to the decomposition of FeAsS and the increase in cyanide leachability. this shows that the refractory character of the ore is caused by the chemical bonding of the gold rather than by the physical inclusion of small, discrete metallic particles in the matrix of FeAsS or FeS₂. The ratio of thef-factors of gold bound in the FeAsS component of a refractory ore and of metallic gold was determined to bef(Au:FeAsS)/f(Au)=1.48±0.09.     

Experimental investigations of the formation kinetics of gold nanoparticles in polymeric media

The kinetics of UV-induced formation of gold nanoparticles in polymethylmethacrylate films doped with chloroauric acid HAuCl₄ is studied. The films are investigated by the absorption spectroscopy and smallangle X-ray scattering methods. The changing size and polydispersity of gold nanoparticles are analyzed during their formation. The growth of gold nanoparticles is determined by the properties of a polymeric matrix and the rate of diffusion fluxes of matter.     

Heating process and damage threshold analysis of Au film coated on Cu substrate for femtosecond laser

The heating processes of a two-layer film assembly of Au padded with Cu irradiated by femtosecond laser pulse are studied using a two-temperature model. It is found that the chosen substantially influence the energy transport, and consequently the temperature variation, and thermal equilibrium time. At the same laser fluence, the different thickness of gold film leads to a change of gold surface temperature. By choosing the thickness of the gold layer in the two-layer film assemblies, the damage threshold of the gold film can be maximized. The results can be used to optimize the damage threshold of gold coating optical components.     

Molecular dynamics simulation of the solidification of liquid gold nanowires

The solidification behavior of liquid gold nanowires with about 1.84 nm in diameter has been studied by using molecular dynamics simulation with an embedded atom potential. It is found the cooling rate has great effect on the final structure of the gold nanowires during solidification from liquid. With the decrease of cooling rates, the final structure of the gold nanowires varies from amorphous to crystalline via helical multi-shelled structure. The face-centered cubic structure of the gold nanowires is proven energetically the most stable form.     

Using surface enhanced Raman scattering to study vibrations of adsorbates on thin metallic overlayers on silver

We have studied the surface enhanced Raman scattering from molecules adsorbed on thin gold overlayers on silver island films. The Raman scattering of gold cyanide species adsorbed on gold overlayers decreases in intensity with gold overlayer thickness between 0.5 – 10 Å . This intensity decrease is consistent with a simple model which takes into account the damping of the electromagnetic resonances of the silver islands by the absorbing gold overlayer. Implications of these findings for the enhancement of Raman scattering from adsorbates on other metals deposited as overlayers on silver will be discussed.     

Two-photon-excited photoluminescence and heating of gold nanorods through absorption of supercontinuum light

Most of lasers used for imaging and heating gold nanorods are single-wavelength lasers and their efficiency to interact with different gold nanorods is limited. In this study, we demonstrated that supercontinuum light could be a fast, effective and energy efficient excitation source for heating of gold nanorods. The photothermal effect and the heating speed of gold nanorods illuminated by a supercontinuum light and femtosecond pulses through two-photon excitation are experimentally studied through using transmission electron microscopy images and photoluminescence images of gold nanorods. It is found that the supercontinuum light improves the heating speed by 39 %, and melts 30 % more of gold nanorods compared with the femtosecond pulse excitation approach. The heating speed of gold nanorods by supercontinuum light depends not only on its polarization states, but also on the pulse width and numerical aperture of its focused beam. It has been found that the supercontinuum is more efficient in heating of gold nanorods, making it potentially valuable for clinical applications.     

Effects of annealing time on the structure,morphology, and stress of gold–chromium bilayer film

In this work, a 200-nm-thick gold film with a 10-nm-thick chromium layer used as an adhesive layer is fabricated on fused silica by the electron beam evaporation method. The effects of annealing time at 300℃ on the structure, morphology and stress of the film are studied. We find that chromium could diffuse to the surface of the film by formatting a solid solution with gold during annealing. Meanwhile, chromium is oxidized on the surface and diffused downward along the grain grooves in the gold film. The various operant mechanisms that change the residual stresses of gold films for different annealing times are discussed.