等离子体光谱光源技术的研究进展

光谱光源是光谱仪器和光谱技术的核心,等离子体光源是原子发射光谱技术的活跃领域之一,电感耦合等离子体(ICP)已成功地应用于原子发射光谱和无机质谱仪器。由于ICP光源采用氩气作为工作气体,耗量较大,降低氩气用量成为近些年来原子光谱技术研究和改进的重要目标。为此目的,已研究过各种低耗氩ICP光源,非氩气ICP光源,微波等离子体光源,射频电容耦合等离子体光源等。综述了近年这些等离子体发射光源的结构,分析性能及特点,以及它们所用工作气体情况。并归纳总结出,评价各种等离子体发射光谱光源应包括:等离子体温度(激发温度,气体温度),电子密度,工作气体种类及用量,元素检出限,光源的稳健性及经济方面等。     

电感耦合等离子体原子光谱光源工作气体的现状与发展

电感耦合等离子体(ICP)光源氩气用量通常超过12L/min,是ICP光谱仪运行分析的最主要的消耗品,价格较贵。现介绍并评论多种低氩气耗量ICP光源,包括低气流炬管、水冷炬管、微型ICP炬管、双原子分子气体光源及混合气体光源等。讨论了节省氩气ICP光源技术的最新发展。     

微波等离子体光谱技术的发展(二)

微波等离子体光源是一类重要的有较强激发能力的原子发射光谱光源,主要包括微波感生等离子体光源,电容耦合微波等离子体光源及微波等离子体炬光源。本文是微波等离子体光谱技术发展的第二部分,主要介绍了电容耦合微波等离子体光源及微波等离子体炬光源的结构原理和性能。并对它们的技术特点和进展进行评述。     

微波等离子体光谱技术的发展(一)

微波等离子体光源是一类有较强激发能力的原子发射光谱光源,主要包括微波感生等离子体光源(MIP),微波电容耦合等离子体光源及微波等离子体炬光源。文章分两部分,第一部分介绍了微波感生等离子体光源的结构原理和性能,并对它们的技术特点和进展进行评述。低功率微波感生等离子体光源用于直接测定溶液中某些痕量金属元素是比较困难的,如Pb,Hg,Se等元素,但它已成功地与气相色谱联用用于测定C,H,O,N,S等难激发的非金属元素。高功率磁场激发的氮-微波感生等离子体光源(N2-MIP),允许使用通用玻璃同心雾化器产生湿试液气溶胶直接进入等离子体核心,等离子体能稳定运行,其分析性能近似于商用ICP光源,且运行费用低廉,是有发展前景的一种新型原子发射光谱光源。     

电感耦合等离子体光谱仪器技术进展与现状

介绍了电感耦合等离子体光谱分析仪器技术的发展历程及主要技术特点,并分别评述了目前三种典型ICP光谱仪器及其技术现状和新进展,它们分别是：顺序扫描型ICP光谱仪、同时型ICP光谱仪及顺序-同时型ICP光谱仪。最后介绍了几种有较好应用前景的光谱新光源：静态高灵敏ICP(SHIP)光源,高功率微波等离子体光源,电容耦合等离子体光源,炬内进样短炬管等。     

电感耦合等离子体原子发射光谱法测定铈矿中微量的砷、锑

采用过氧化钠熔融试样，用盐酸调节试液酸度，对电感耦合等离子体原子发射光谱（ICP－AES）法同时测定铈矿中微量砷和锑进行了研究，考察了铈基体及共存元素，试液酸度及介质等因素对砷和锑的光谱和非光谱影响。     

电感耦合等离子体发射光谱法测定固体废物浸出液与消解液中六价铬

本法建立了电感耦合等离子体发射光谱法测定固体废物中Cr(Ⅵ)的测定方法。将HJ/T299—2007硝酸硫酸法浸提的浸出液,用聚氯化铝絮凝剂将Cr(Ⅲ)沉淀除去,采用电感耦合等离子体发射光谱法测定Cr(Ⅵ)。同时,将HJ 687—2014碱消解/原子吸收法测定Cr(Ⅵ)总量也采用电感耦合等离子体发射光谱法测定。研究了聚氯化铝的用量、仪器工作条件、共存离子的干扰等因素。结果表明,ICP—AES法的检测线低、线性范围宽、线性相关系数为0.9996,方法的精密度为0.58﹪～3.75﹪,回收率为90﹪～114﹪,避免了溶液基体颜色的干扰,适合皮革固体废物浸出液和碱消解液中Cr(Ⅵ)含量的测定。     

气相色谱用微波等离子体炬原子发射光谱检测器的Cl,Br,I响应特性的研究

 将微波等离子体炬原子发射光谱检测器(MPT-AED)用作气相色谱检测器,采用氩气作为工作气、载气和尾吹气,优化了气体流量参数;为了防止被测物质在管壁上的沉积,考察了氧气作为气相色谱-微波等离子体炬-原子发射光谱检测器(GC-MPT-AED)清洗气时对Cl,Br,I3种元素发射信号的影响。为了考察检测器的分析性能,研究了GC-MPT-AED对有机化合物中Cl,Br,I3种元素的检出限、线性范围、精密度及其响应特性,并将其结果与气相色谱-电感耦合等离子体-原子发射光谱检测器(GC-ICP-AED)的结果作了比较,结果表明该仪器对Cl,Br的检测能力优于GC-ICP-AED的结果,线性范围与GC-IC     

气相色谱-微波等离子体炬原子发射光谱检测器及其响应特性的研究

报道了一种气相色谱用微波等离子体炬原子发射光谱检测器(GC-MPT-AED),以氩气为载气和等离子体工作气体,氧气为清洗气和屏蔽气,研究了MPT-AED对有机化合物中碳元素的响应特性,探讨了氧气作为GC-MPT-AED屏蔽气对碳元素检测性能的影响.     

乙醇对低功率ICP光源的影响

研究了在低功率他激高频发生器条件下，乙醇对ICP－AES的影响。乙醇引入试液后导致粘度增加，表面张力、密度下降，试样提升量降低，等离子体激发温度和气体温度下降，Ca,Mg,Ni,Cu,Pb等常见元素灵敏度降低而稀土元素的灵敏度得到改善。讨论了乙醇对低功率ICP光源的影响。     

In situ access to white light‐emitting fluorescent polymer nanocomposites via plasma‐ignited frontal polymerization

We describe a facile fabrication of white light‐emitting cadmium sulfide (CdS)‐poly(HEA‐co‐NVK) nanocomposites [2‐hydroxyethyl acrylate (HEA) and N‐vinylcarbazole (NVK)] via plasma‐ignited frontal polymerization (PIFP), a novel and rapid reaction mode of converting monomers into polymers in minutes. Frontal polymerization was initiated by igniting the upper side of the reactant with plasma. Once initiated, no additional energy was required for the polymerization to occur. The chemical functional groups of the as‐prepared nanocomposites were thoroughly investigated using Fourier transform infrared spectra. The dependence of the front velocity and front temperature on the initiator concentration and weight ratios of HEA/NVK was also investigated in detail. Perhaps more interestingly, the white light‐emitting materials synthesized by ingeniously incorporating the compensating colors of yellow emitting from 3‐(trimethoxysilyl)‐1‐propanethiol‐capped CdS nanocrystals and blue emitting from carbazole‐containing polymer were conveniently applied onto a commercial UV light‐emitting diode (LED) to generate white LEDs. The subtle change in the weight ratios of CdS/NVK can significantly impact the color hue. The white light becomes gradually colder with the increase of NVK, but becomes gradually warmer with the increase concentration of CdS nanocrystals. In a broad perspective, these white light‐emitting materials designed by PIFP approach will open a new pathway to develop “QD‐polymer nanocomposite down‐conversion LED” in a fast and efficient way. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Particle transport in a He-microchip plasma atomic emission system with an ultrasonic nebulizer for aqueous sample introduction

The transport efficiency of dried particles generated from an ultrasonic nebulizer (USN) was studied to improve the analytical performance of a lab-made, He-microchip plasma system, in which a quartz tube (~ 1 mm i.d.) was positioned inside the central channel of a poly(dimethylsiloxane) (PDMS) polymer chip. The polymer microchip plasma has the advantages of low cost, small size, easy handling and design, and self-ignition with long stabilization (> 24 h). However, direct introduction of aqueous solution into the microplasma for the detection of metals remains problematic due to plasma instability. In addition, the much smaller size of the system can cause signal suppression due to low transport efficiency. Therefore, knowledge of particle transport efficiency in this microplasma system is required to enhance the sensitivity and stability. The weight of transported particles in the range of 0.02 to 10 mg m^− 3 was measured using a piezobalance with a precision of 0.4–17.8%, depending on the operating conditions. The significant effects of the USN operating conditions and the physical properties of the tubing, namely, length, inner diameter and surface characteristics, on the number of particles transported from the nebulizer to the microplasma were studied. When selected metals, such as Na, Mg and Pb, at a concentration of 5 mg L^− 1 were nebulized, transported particles were obtained with a mass range of 0.5–5 mg m^− 3, depending on atomic weights. For application of the He-rf-microplasma, the atomic emission system was optimized by changing both the radio frequency (rf) power (60–200 W) and cooling temperature of the USN (− 12–9 °C). The limits of detection obtained for K, Na and Cu were 0.26, 0.22, and 0.28 mg L^− 1, respectively. These results confirmed the suitable stability and sensitivity of the He-rf-PDMS microchip plasma for application as an atomization source.     

Compact plasma source for removal of hydrocarbons for surface analysis

A low–energy, constricted‐anode Anders‐type plasma source was built and tested for the chemical removal of adventitious carbon on surfaces. Oxygen plasma, generated in the source, extends to the sample surface through an aperture in the anode. This plasma reacts with surface hydrocarbons and removes them in less than a minute without influencing the intrinsic surface stoichiometry of nonoxidizing samples such as minerals, glasses, and metal oxides. Adventitious carbon removal is critical for accurate binding energy determination and quantitative measurements in XPS and AES, particularly in multicomponent materials. We measure the plasma to be composed primarily of O⁺ and O₂⁺, with minor H⁺, H₂⁺, and O⁺⁺ components. Ion energy distributions were measured for O⁺ and O⁺⁺ and show all emitted ions have energies less than 50 eV, confirming chemical desorption as the primary removal mechanism. The plasma source, easily built ‘in house’, is compact and can be mounted on a 2.75‐in flange for in situ specimen cleaning prior to surface analysis. Copyright © 2009 John Wiley & Sons, Ltd.     

辉光放电灯在分析中的应用

辉光放电灯（GDL）作为光源被广泛应用于固体样品的直接分析中,文章综述了GDL的发展过程、类型及其在分析中的应用。     

Determination of radiation power of the solar-simulated light source

Calorimetric method for the determination of radiation power of the solar-simulated light sources has been proposed. The application of the differential scanning calorimetry guarantees very high sensitivity (1 mW) of the measuring property, independent of the wavelength (within 300-1200 nm). The applied method yields reliable calibration curves of the radiation power vs. wavelength with good accuracy. This revised version was published online in July 2006 with corrections to the Cover Date.     

X-ray imaging during plasma-source ion implantation

Plasma source ion implantation (PSII) is a technique for modifying stafaces that places the object to he modified directly into a plasma and then negatively pulse biases the object so as to implant positive ions. If the voltage is high enough, X-rays can he generated by electrons that are also accelerated by the pulse. This work describes techniques for imaging and characterizing the X-rays A pinhole camera was used to image the X-rays being emitted as electrons collided with surfaces in the chamber. The images show that X-rays are generated at the chamber walls and near the target. The time dependence of these X-rays during each pulse was examined using a PIN diode X-ray detector. Then, using another X-ray sensor and pulseheight analyzer, the spectra of the emitted X-rays was determined. The object is to relate the X-ray intensity and spectrum to the temporal and spatial values of the implantation dose so that it may he used as a process monitor and a control sensor.     

Dual-light source excitation for mode-filtered light detection

The sensitivity of a multi-channel mode-filtered light detection system has been enhanced by using a dual-light source irradiation technique. The detection system was constructed from an annular column consisting of a bare optical fibre inserted into a capillary. Sample was introduced through the gap between the fibre and the capillary. A multi-channel charge-coupled device was set on the side of the capillary at which four detection windows could be simultaneously monitored. The changes in the intensities of the mode-filtered light on exposure to various concentrations of ethanol samples from each detection window were monitored. The theoretical studies on the sensitivity of detection of the detection system using dual-light source irradiation have been described. The sensitivity of detection was enhanced when a dual-light source instead of a single-light source was employed. The working concentration range for ethanol was 0-80% (v/v) ethanol. The limit of detection was determined to be 1% (v/v) ethanol. The proposed method has been successfully applied to the determination of ethanol contents of some wine samples. The results were satisfactory compared with values obtained from a standard reference method.