氧屏蔽氩微波等离子体炬的背景发射及其中某些元素发射？…

氧屏蔽氩微波等离子体炬（ＯＳ－Ａｒ－ＭＰＴ）是对Ａｒ－ＭＰＴ新光源的一个重大改进。本文主要探讨了屏蔽气氧流量变化时对该新光源背景发射光谱及某些元素的原子线、离子线发射的影响。结果表明,该光源简单的背景发射十分有利于作原子发射光谱分析,同时它对多数元素的原子发射线信背比都有明显的改善,是一种很有发展前途的新光源。     

电感耦合高频等离子体光源中谱线激发特性的研究

本文测量并比较了遵守局部热平衡的交流电弧光源和非热平衡的Ar ICP与N_2/Ar ICP光源的激发温度、多元素离子线/原子线的强度比,实验指出在ICP光源中,(激发电位+电离电位)与亚稳态氩原子的能量相近的离子谱线发射显著增强,表明亚稳态氩和潘宁电离在该光源的激发过程中所起的特殊作用。     

锂的石墨炉原子发射分析方法的研究

痕量锂在人体内已成为不可缺少的元素,对疾病的控制或临床上的诊断以及对环境、医学及生物的研究都有明显的意义。由于一般分析方法灵敏度不高,对锂的检测比较困难。Ottaway等采用石墨炉原子发射法以标准石墨管测定锂和其它某些元素,检出限比火焰发射法和石墨炉原子吸收法有明显的改善,并应用于纯铜中痕量锂的测定。Matousek等研究了锂的石墨炉原子发射方法,在入口狭缝处使用档光技术降低背景发射,提高了     

石墨炉原子发射分析法

1975年Ottaway等提出将石墨炉作为发射源用于原子发射分析,Molnar等也研究了从玻璃态碳炉的原子发射,此后,在基础研究和实际应用等方面的工作已有不少报导。现有研究结果表明,石墨炉原子发射法(GFAES)已能实际应用于一些元素的定量分析,并具有某些特点。如灵敏度高,据报导有40余种元素的检出极限低于或远低于1μB/ml,其中K、Na、Li、Ba等元素的检出极限远比石墨炉原子吸收法(GFAAS)低。此外,和其它发射法相比,尚有光谱线干扰少、背景发射较稳定、电离干扰小等优     

高钙基体在DCP光源中的分析特性

一般认为三电极DCP光源的基体成分的影响较小,但一些研究指出,存在易电离元素会引起其它元素发射强度的增强。碱土金属如钙由于在等离子体光源中强烈发射对一些测定元素有严重的背景干扰。本工作对高钙基体在DCP光源中的分析特性:激发温度轴向分布,对测定元素谱线强度的增强效应、背景干扰及校正方法以及谱线选择等进行了研究,同时还对高钙基体的测定重现性进行了探讨,并提出了改善办法。     

分子发射腔分析含磷有机化合物

某些元素在火焰中的分子发射现象早就为人们知晓,特别是磷、硫等元素在屏蔽的氢火焰中发射特征的绿、蓝色光,六十年代即被应用于色谱检测。而Belcher等人1973年提出的时间分辨分子发射腔分析法(缩写MECA),则更进一步开拓了利用分子发射现象快速、灵敏、简易地分析某些非金属元素的新前景。有关分子发射腔分析的进展已有专文评     

原子发射法测定工业废水地下水中可溶性钾钠

工业废水地下水中的钾钠元素,通常采用原子吸收光谱法进行测定,而对仪器上所配有的原子发射光谱功能,一般使用较少.作者利用P-E 3030型原子吸收光谱仪上所提供的原子发射测定程序对其进行测定,并与原子吸收光谱测定结果进行比较,两者无显著性差异.同时利用原子吸收光谱仪的发射法功能测定钾钠元素,不需要空心阴极灯,因而更加方便、经济,充分利用了仪器功能.     

高分辨连续光源原子吸收光谱法对土壤中磷的测定

磷元素在适宜的空气-乙炔火焰中可形成PO双原子分子,PO分子的部分吸收谱线具有原子谱线的轮廓和强度.该文主要研究了利用连续光源原子吸收光谱法,在空气-乙炔火焰条件下测定PO分子的吸光度值,从而测定土壤样品中的磷元素.实验研究了测定过程中可能存在的光谱干扰和化学干扰、乙炔/空气流速比、燃烧器高度对PO双原子分子吸光度的影响,以及不同消解方式对测定结果的影响.在优化的实验条件下,PO 246.40 nm的检出限为20 mg/L.通过对土壤标准物质中磷元素含量的测定比对证明,连续光源原子吸收光谱法是一种测定土壤中磷元素含量的简单、快速的方法.     

Zeeman原子吸收光谱分析法中谱线轮廓的研究 Ⅰ.原子发射谱线、原子吸收谱线和Zeeman原子吸收谱线轮廓间重叠关系图的建立

详细报道用理论计算和绘制的37个元素分析线的发射线轮廓、吸收线轮廓和Zeeman分裂后的吸收线轮廓,并建立了在原子吸收光谱法中三者轮廓间的重叠关系图.     

Zeeman原子吸收光谱分析法中谱线轮廓的研究I.原子发射谱线.原子吸收谱线和Zeeman原子吸收谱线轮廓间重叠关系图的建立

详细报道用理论计算和绘制的37个元素分析线的发射轮廓. 吸收线轮廓和Zeeman分裂后的吸收线轮廓, 并建立了在原子吸收光谱法中三者轮廓间的重叠关系     

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。     

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.     

微波等离子体炬耦合方式的研究

采用气动雾化连续进样、端视观测法,考察了微波等离子体炬原子发射光谱法中等离子体Ar线的背景发射以及Al,Mg,V等元素的信号发射强度随天线耦合连接点位置的不同而发生的变化.结果表明,当天线位于炬管顶端,即天线距离活塞3λ/4和λ/4时均能获得较好的等离子体,λ/4略好,信号发射强度和信背也较大,只是精密度略差一些.初步探讨了MPT炬管的电磁场结构.     

低功率微波等离子体炬原子发射光谱法的研究——超声雾化进样测定金、银、铂、铑、钯

本文提出一种测定贵金属元素的微波等离子体炬原子发射光谱法(MPTAES)。采用自制的超声雾化微量进样装置进样,以氩气为工作气体,探讨了观察高度,微波功率、体系介质、氩气流量和共存元素对被测元素发射信号的影响。选用合适的分析线和MPT光源的工作参数,其方法的检出限分别为5.8(Au)、0.5(Ag)、12(Pt)、1.6(Rh)和t 1.0ng/ml(Pd)。实际样品中金和银的测定结果是令人满意的。     

The application of a double voltage modulation technique to a glow discharge source with a supplementary electrode

The Ar spectral lines are suppressed in glow discharge source atomic emission spectroscopy by a double voltage modulation technique with a supplementary electrode. The voltage is modulated between two levels, typically 350 and 700 V. At the lower voltage level mainly the Ar emission occurs where at the higher voltage level both the Ar and the metal atoms sputtered from the sample contribute to the emission. The power supply of the supplementary electrode is switched on when the glow discharge passes from operation at 700 V to 350 V. The intensity of argon gase lines is regulated by the current applied to the supplementary electrode at that period. Therefore, there is no need for electronical amplification and lower voltage adjustment of two operation modes. This modified DVM technique has been applied to the determination of Si and Cu in Al- samples. The suppression of Ar lines is possible, and the elements can be determined without Ar interferences.     

The application of a double voltage modulation technique to a glow discharge source with a supplementary electrode

The Ar spectral lines are suppressed in glow discharge source atomic emission spectroscopy by a double voltage modulation technique with a supplementary electrode. The voltage is modulated between two levels, typically 350 and 700 V. At the lower voltage level mainly the Ar emission occurs where at the higher voltage level both the Ar and the metal atoms sputtered from the sample contribute to the emission. The power supply of the supplementary electrode is switched on when the glow discharge passes from operation at 700 V to 350 V. The intensity of argon gase lines is regulated by the current applied to the supplementary electrode at that period. Therefore, there is no need for electronical amplification and lower voltage adjustment of two operation modes. This modified DVM technique has been applied to the determination of Si and Cu in Al- samples. The suppression of Ar lines is possible, and the elements can be determined without Ar interferences.     

Emission characteristics of the dielectronic recombination line of atomic Cu and selectively excited ionic Cu line by resonance charge-transfer collision in a low-pressure laser-induced plasma.

Emisson spectra and time-resolved two-dimensional (2D) emission images of the electron-ion dielectronic recombination (i.e. a reversal process of auto-ionization) line of neutral Cu atoms, the selectively excited Cu ionic line, and normal Cu atomic line were observed for understanding the excitation mechanisms of Cu neutral and ionic lines in a low-pressure laser-induced plasma (LP-LIP) of Ar. From the observations, the number of charged particles around the emitting species seems to increase with increasing Ar pressure. Different time-resolved 2D emission images were observed among the selectively excited Cu ionic line and other Cu emission lines resulting from the different excitation mechanisms of the respective emission lines. Collisions of the second kind and electron-ion recombinations were found to be one of the major excitation mechanisms of Cu in Ar LP-LIP.     

原子发射光谱分析

本文是《分析试验室》期刊定期评述中“原子发射光谱分析”课题的第一篇评述文章。文中对1987～1990年期间我国原子发射光谱分析(AES)领域所取得的进展作了全面评述。内容包括概述、火焰发射光谱法、电弧发射光谱法、火花发射光谱法、电感耦合等离子体原子发射光谱法、直流等离子体原子发射光谱法、微波等离子体原子发射光谱法、亚稳态能量转移发射光谱法、激光显微发射光谱法、空心阴极灯和Grimm灯发射光谱法等方面。     

Emission spectroscopic studies of Grimm-type glow discharge plasma with argon-helium gas mixtures

The effect of argon/helium pressure ratios on the emission intensity of various Ar II lines is investigated for a Grimm-type glow discharge radiation source, operated with Ar-He mixtures. The relative intensities of the Ar II lines are altered significantly by mixing helium with argon. It is found that the population of the Ar⁺ excited states can be redistributed through He-Ar collisional energy transfer. The energy level of the He singlet metastable state (¹S₀,20.62 eV) is very important for these processes. If the excitation energy of Ar II lines is higher than that of the He singlet metastable, strong quenching of the Ar II line intensity is observed. However, when the excitation energy is slightly lower, some of the Ar II lines are enhanced by adding helium to the argon plasma. Energy exchanges between the Ar⁺ doublet term states and the He singlet metastable are favoured because the total spin remains unchanged before and after the He-Ar collisions. Furthermore, the helium mixing also exerts a great influence on the emission intensities of the elements sputtered from the cathode of the discharge lamp. The enhancement of Al I and Al II emission intensities at suitable Ar-He mixture ratios is discussed for when aluminum is employed as a cathode material.     

Use of microwave plasma torch atomic emission spectrometry for the determination of silicon

 A method for the elimination of matrix effects was developed for the determination of trace amounts of silicon by microwave plasma torch atomic emission spectrometry (MPT-AES). The sample solution was introduced into the MPT with a pneumatic nebulizer (PN). When Ar was used as both carrier and support gas, a detection limit of 10.8 ng/ml was obtained. The precision was 4.2% (RSD). The characteristics of the emission spectrum of silicon in MPT was studied in detail. The interference of some concomitant cations with the silicon emission was eliminated by incorporation of a cation-exchange column into the flow injection system. The method has been applied to analyze some practical samples and the results obtained are satisfactory. Received: 23 October 1995/Revised: 16 April 1996/Accepted: 20 April 1996