电热蒸发进样低功率MPT—AES测定铜,锌,镉的研究

微波等离子体炬(MPT)是一种具有类似ICP炬管结构的新型等离子体光源,该光源的基本性质已进行了详细的研究。本文采用自制的低功率MPT为激发光源,以氧为工作气体,用微型电热蒸发装置进样,测得铜、锌和镉的检出限分别为3.3、1.4和1.7ng/mL。考察了碱金属元素对铜、锌和镉发射信号的影响,该方法应用于钢样中铜的测定,结果较好。     

等离子体光谱光源技术的进展

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。     

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。     

介孔二氧化钛/导电碳毡光电极的制备及光电催化性能

以四氯化钛为无机钛源,十六烷基三甲基溴化铵为模板剂,通过水热合成法制得无机物钛前驱体溶液.以导电碳毡(CCF)为载体,在超声波辅助下用浸渍提拉法负载钛前驱体,通过高温煅烧得到介孔二氧化钛/导电碳毡(MPT/CCF)光电极材料,对样品的结构进行了表征,并以室内污染物气相苯甲醛为目标降解物,通过评价不同煅烧温度和不同负载次数下MPT/CCF的光电催化性能优化了MPT/CCF的制备工艺条件,探讨了催化降解条件(温度、湿度、偏电压)对协同增效机制的影响.结果表明,相对于纯介孔二氧化钛(MPT),MPT/CCF具有较小的粒径尺寸、更大的比表面积和较均匀的孔径分布,这归功于CCF对晶粒生长的抑制作用.其中负载2次MPT并在500℃下煅烧的2-MPT/CCF-500样品具有最高的光电催化活性,主要是由于其具有完善的晶型、均匀的介孔分布和高浓度的羟基自由基,并且在重复使用过程中也具有很高的光电催化活性.最佳的催化条件为温度35℃、相对湿度55%、偏电压10 V.     

低功率微波等离子体炬（MPT）光源基本性质的初步研究

对低功率微波等离子体炬(MPT)光源基本性质进行了初步研究,采用“双线法”测定了有、无样品引入时光源中激发温度随观测高度的变化;测定了Zn、Cd、Mg的原子线和离子线发射强度随观测高度的变化;还研究了一些实验参数对等离子体激发温度的影响。     

辉光放电光源在铝合金发射光谱分析上的初步应用

前言辉光放电光源的稳定度高,只要有精度好的检测系统,可保证分析结果有很高的精密度。直接进行固体块样的合金组分元素分析,是这种光源的特长之一。用辉光放电光源作铝合金的分析,国外也有报导。因铝合金极易氧化,试样表面易形成氧化膜,所以试样不易产生正常的剥离,而且预燃时间往往很长又无规律,因而分析再现性不好。浅田庄太郎等认为铝合金的分析,用辉光放电光源是很困难的。他们在试验中还发现了第三元素的影响。试样中只要含有铜,溅射量就增大,使准确度变坏。Dogan研究了铜-     

涂层的辉光放电光谱分析及精密度

本文研究了辉光放电光源的基本特性并应用到涂层表层的组成分析,分析结果和电子探针的结果相一致,证明本方法可靠。辉光放电光源分析的精确度比火花光源有显著的提高,如配用光量计,可进行高含量元素的分析。     

现代光学发射光谱分析光源

气体燃烧火焰是120年前原子发射光谱分析的创始人克希霍夫和本生应用的第一个光源。为了激发金属电极的光谱,他们也应用了火花放电。后来,为了分析气体又开始利用在大气压下的电弧放电和低压气体放电管。最近20年的特征是传统的光源现代化,并研究出许多新光源。在现代光学发射光谱分析中应用的光源及其改进型式约有数十种。下面列出了光源的分析特性、决定分析特性的物理特征及光源的技术参数:     

低温等离子体对高分子材料表面的改性

低温等离子体是以低气压放电(辉光、电晕、高频、微波)产生的电离气体,其中蕴含着丰富的活性粒子,可以引起种种化学反应。处于非平衡态的低温等离子体,其电子温度 T_e>>离子温度 T_i 和气体温度 T_g。如辉光放电或射频放电产生的低温等离子体,其 T_e≈10~4K, T_g则略低二个数量级。在低温等离子体条件下进     

微波等离子体增强辉光放电光源激发温度的研究

研究了一种改进型的微波等离子体增强辉光放电光源在光谱分析中的应用，对其重要的参数指标－激发温度进行了较为较细的考察。结果表明引入微波等离子体后辉光放电的激发温度明显高于单纯辉光放电时的激发温度。     

Preliminary spectroscopic experiments with helium microwave induced plasma produced in air by use of a new structure: the axial injection torch

In this experimental study we have used spectroscopic methods to characterize helium plasma obtained by means of a novel waveguide-fed microwave plasma torch at atmospheric pressure, the axial injection torch. This device produces a “plasma flame” by coupling high frequency (HF) power at 2.45 GHz to the discharge. Various flame parameters (namely the electron density number and the electron and gas temperatures) have been determined by using spectroscopic diagnostic techniques that provided an estimate in terms of the helium flow rate, absorbed HF power and axial position in the experiments. These preliminary results suggest some departure from local thermodynamic equilibrium (LTE) and seem to indicate the utility of the discharge as an excitation source for emission spectroscopy. Comparison with other microwave torches already described in the literature is made in terms of the electron density and the electron and gas temperature.     

MPT-AES测定奶粉中的Ca和Fe

用微波等离子体(MPT)为激发光源,氩气为等离子体工作气体,用气动雾化进样,采用标准曲线法研究了微波等离子体炬原子发射光谱法(MPT-AES)测定奶粉中Ca、Fe的方法。详细考察了溶液中HCl浓度、HNO3浓度、微波前向功率、载气流量、工作气流量等实验参数对测定的影响,同时考察了共存元素钠、镁、锌对钙和铁发射强度的影响。     

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。     

Photographic plasma images and electron number density as well as electron temperature mappings of a plasma sustained with a modified argon microwave plasma torch (MPT) measured by spatially resolved Thomson scattering

In this work the determination of electron number densities and electron temperatures for the case of a modified microwave plasma torch (MPT) operated at 100 W with argon by means of spatially resolved Thomson scattering measurements and photographic records of the MPT at different working conditions are reported. With an internal gas flow of 500 ml min⁻¹ and an outer gas flow of 200 ml min⁻¹ electron number densities and electron temperatures are in the range of 10²⁰ m⁻³ to 10²¹ m⁻³ and of 16 000–18 000 K, respectively. When increasing the internal gas flow from 500 to 900 ml min⁻¹ the plasma becomes longer and the maximum electron number density increases by a factor of 2. An increase of the outer gas flow from 200 to 700 ml min⁻¹ leads to a lifting of the whole plasma from the burner edge with the maximum electron number density remaining unchanged. An increase of the power from 80 to 180 W was found to lead to higher electron number densities whereas the electron temperatures remain unchanged. The addition of 1.2 mg min⁻¹ of water vapor to the internal gas flow leads to a decrease of the electron number density from 4.7×10²⁰ m⁻³ to 2×10²⁰ m⁻³ and to an increase of the electron temperature from 16 000 to 22 000 K. In order to document the influence of the internal gas flow rate, water introduction and introduction of easily ionized elements on the visible plasma shape digitally recorded photos of the plasma are presented.     

Microwave plasma torch analytical atomic spectrometry

The microwave plasma torch (MPT), as a relative new source, has found extensive use in atomic spectrometry. In this review, the fundamental features and characteristics of the MPT are summarized and compared with other kinds of analytical atomic sources, such as the more popularly used inductively coupled plasma (ICP), the direct current plasma (DCP), as well as other kinds of microwave plasmas (MWPs). Since the MPT offers some attractive features, it has been used as an excitation source for atomic emission spectrometry (MPT-AES), including the atomic emission detection (AED) for gas chromatography (GC), liquid chromatography (LC) and supercritical fluid chromatography (SFC). Also, it has been used either as an ionization source for atomic mass spectrometry (MPT-AMS) or an atomization source for atomic fluorescence spectrometry (MPT-AFS). The historical development and recent improvements in these MPT atomic spectrometric techniques are evaluated with emphasis on the analytical advantages and limitations. In addition, the future research directions and the application prospects of MPT atomic spectrometry (MPT-AS) are discussed.     

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.     

An experimental study of asymmetry in an argon inductively coupled plasma torch using a relaxation method

A relaxation method is used to undertake an experimental study of the degree of cylindrical symmetry present in an argon inductively coupled plasma torch, ICP. This technique, in effect a direct comparison between two different parameters, the electron (T_e) and gas (T_g) temperatures in the torch, is shown to be a very sensitive indicator of axisymmetry. Measurements using this technique delineate areas of axisymmetry in the ICP, and show that axisymmetry is significantly dependent on the observation height and coolant gas flow-rate.     

An improved microwave plasma torch for atomic spectrometry

The analytical performance of a microwave plasma torch was improved through mechanical alterations. Several problems reported in earlier designs were addressed: the ignition and stabilization of a helium plasma in the MPT was difficult; high powers were required to both ignite and operate the plasma; otherwise, the plasma would erratically change from an annular to a filament type discharge. In the new torch, the helium discharge was stabilized by replacing the copper central tube with one made of quartz. In addition, air entrainment was alleviated through use of a sheathing gas. This modification simplified the background mass spectrum and raised the effective ionization temperature of the discharge. A detailed schematic diagram of the new microwave plasma torch is presented.