重量法和光泽度法检测改性聚丙烯雾化性能

采用重量法和光泽度法检测改性聚丙烯雾化性能,研究了试样形式和不同溶剂对检测结果的影响。结果表明,采用重量法时,料粒冷凝组份G比圆片高,故圆片雾化性能好,且不同溶剂对改性聚丙烯材料冷凝组份G的增加程度受组分分压、体系总压和组分间相互干扰的影响;采用光泽度法时,料粒雾化值FJ比圆片低,故圆片雾化性能好,且不同溶剂对改性聚丙烯材料雾化值FJ的降低程度受组分分压、体系总压和组分间相互干扰的影响;雾化重量法和光泽度法测试结果不具备可比性。此外,邻苯二甲酸二辛酯标样放置时间对重量法结果有较大影响。     

气动雾化进样时微波等离子体炬作为激光发源的性能研究

以气动雾化进样研究了微波等离子体矩（ＭＰＴ）放电作原子发射光谱法激光发源的性能，包括ＭＰＴ的获得、操作参数的影响、样品引入及其分析性能，并与微波诱导等离子体进行了比较，证明了ＭＰＴ放电作激发光源有良好的分析性能。     

气动雾化进样时微波等离子体炬作为激发光源的性能研究

以气动雾化进样研究了微波等离子体炬（ＭＰＴ）放电作原子发射光谱法激发光源的性能，包括ＭＰＴ的获得、操作参数的影响、样品引入及其分析性能，并与微波诱导等离子体进行了比较，证明ＭＰＴ放电作激发光源有良好的分析性能．     

超声雾化进样微波诱导等离子体原子发射光谱法测定痕量磷的研究

本文提出了一种测定水溶液样品中痕量磷的微波诱导等离子体原子发射光谱法(MIPAES)。样品经超声雾化并去溶后引入等离子体。考查了Ar和He MIP中磷的发射光谱特性和一些实验参数对磷发射强度的影响。用Ar和He作工作气体时,检出限分别为0.03和0.0045μg/ml,方法的相对标准偏差小于5％。     

我国超细铜粉研究及生产现状

概述了目前超细铜粉制备方法,包括球磨法、等离子体法、γ射线辐照射法、雾化法、超声电解法、电解法、微乳液法、溶胶-凝胶法、化学还原法等的研究现状,介绍了清华大学核能与新能源技术研究院采用的预还原-复合还原法.同时,对我国的铜粉消费与生产现状作了分析,并对我国今后超细铜粉研究作了展望.     

一种可用于微波等离子体炬原子发射光谱法的热雾化系统

建立了一种新的热雾化系统，用蠕动泵代替高压泵，去掉了加热管部分，使整个热雾化系统更加紧凑，经济，并将其用于微波等离子体炬（ＭＰＴ）－原子发射光谱法（ＡＥＳ），考察了实验参数的影响，与气动雾化相比，对Ｍｇ，Ｐｂ的检出限改善了５～１０倍，同时发现本装置具有元素选择性增强的现象。     

一种新型的ICP-AES用低功率微波热雾化系统

热雾化法自问世以来 [1 ,2 ] ,就以其较高的雾化效率及传输效率受到学者们的普遍重视 .最近 Bordera等[3] 提出了一种新的热雾化系统 (该系统采用聚焦微波炉作热雾化系统中液体样品的热源 ,即微波热雾化系统 ,简称 MWTN) ,同时还考察了实验变量对雾滴粒径分布的影响 ,并预期 MWTN具有较高的雾化效率 .本文所提出的热雾化系统与 Bordera等所建立的 MWTN系统在原理上虽然相同 ,但由于采用了新的微波器件 ,所需功率大大降低 ,因此 ,是一种新的低功率 MWTN系统 .在本实验中 ,我们对酸的浓度、载气流量、样品提升量等参数对 Mg的发射强度…     

氢化物发生辅助雾化火焰原子吸收法测定水中铅

研究了一种提高火焰原子吸收测定铅灵敏度的新方法——氢化物发生辅助雾化的火焰原子吸收法；方法采用硼氢化钠与铅(Ⅳ)在原火焰原子吸收雾化器喷口处反应生成氢化物，以提高火焰原子吸收法的雾化效率；采用重铬酸钾一酒石酸预处理体系，重铬酸钾氧化样品中铅(Ⅱ)为铅(Ⅳ)，酒石酸稳定铅(Ⅳ)的亚稳态化合物；对各种实验参数和干扰情况也进行了研究；方法操作简单、快速，灵敏度比通常的火焰原子吸收法提高了6．8倍；检出限(K=3，n=11)为6．64μg/L，线性范围为0．021～3．2mg／L；测定水样的回收率达94％～99％。     

电感耦合等离子体原子发射光谱法中悬浮液直接进样技术的研究与应用的进展

对电感耦合等离子体原子发射光谱法(ICP-AES)中的悬浮液直接进样技术的研究及应用的进展作了评述。文中引用文献涉及年份为1988~2005年。主要的评述内容包括试样制备方法、仪器装置、校准方法、影响悬浮液进样中的传输效率和雾化效率及分析结果可靠性的因素,以及此技术的分析应用(引用文献47篇)。     

原子光谱分析中的浆液雾化进样

提出了ICP-AES／MS方法中浆液雾化进样问题。叙述了均匀与稳定的浆样制备方法,包括使用添加剂和pH调节。讨论了颗粒大小分布、zeta电位测定等浆样稳定性的表征方法。评述了校准曲线法、标准加入法和本征内标法等校准方法。     

High-performance flow atomic spectrometry: New nebulization techniques,on-line speciation and on-line sample pretreatment

An interface-free combination of HPLC separation techniques and methods for element determination by atomic spectrometry can be achieved by hydraulic high-pressure nebulization (HHPN). With high-temperature HHPN (300 ( degrees )C) super heated liquids can be nebulized providing aerosol yields of up to 90% in flame AAS. This new nebulization method combines the advantages of HHPN and thermospray techniques (very small aerosol droplets, high aerosol yield, nebulization of saturated salt solutions).     

High-performance flow atomic spectrometry: New nebulization techniques, on-line speciation and on-line sample pretreatment

An interface-free combination of HPLC separation techniques and methods for element determination by atomic spectrometry can be achieved by hydraulic high-pressure nebulization (HHPN). With high-temperature HHPN (300^°C) super heated liquids can be nebulized providing aerosol yields of up to 90% in flame AAS. This new nebulization method combines the advantages of HHPN and thermospray techniques (very small aerosol droplets, high aerosol yield, nebulization of saturated salt solutions).     

Use of a multi-tube Nafion® membrane dryer for desolvation with thermospray sample introduction to inductively coupled plasma-atomic emission spectrometry

A multi-tube Nafion^® membrane dryer used as a part of a desolvation system in conjunction with thermospray nebulization was optimized and characterized with inductively coupled plasma-atomic emission spectrometry (ICP-AES). Either argon or nitrogen could be used as the sweep gas, and optimum conditions were found to be at low temperature and low sweep gas flow rate. Analyte sensitivity was not significantly affected by placing the membrane between the plasma and the nebulizer, although about 20% of the analyte entering the dryer is lost within the dryer. A dual role of the membrane dryer was demonstrated. As a secondary step within the desolvation system, it enabled a high desolvation efficiency of 99.94% for aerosols from 1% (v/v) nitric acid. Plasma solvent load could be reduced to 0.9 mg min⁻¹ with a tap water cooled condenser combined with the membrane dryer, compared to 21 mg min⁻¹ with the normal chilled condenser desolvation system. Meanwhile, the membrane was also found to act as a pulse dampener, eliminating the plasma pulsation in the central channel caused by thermospray nebulization and thus improving the analytical performance of the system. The average relative standard deviations (RSD) with the optimized membrane/thermospray system were 0.83% and 0.60% for the background and analyte signals, respectively, which were reduced by a factor of 1.9 and 2.7 for the background and analyte signals, respectively, compared to thermospray without the membrane desolvation, and were essentially identical to those obtained with pneumatic nebulization sample introduction. The improvements in detection limits with the membrane/thermospray system were 1.2–3.0 times with an average factor of 1.8 compared to thermospray without the membrane dryer, and 18–68 times with an average factor of 39 compared to the standard pneumatic nebulization sample introduction system without a desolvation unit. The detection limits for Mn, Mg, Cr and Cd with the present thermospray/membrane system were comparable to those reported for pneumatic nebulization ICP mass spectrometry.     

Characterization of aerosols generated by thermospray nebulization for atomic spectroscopy

The performance of an inductively coupled plasma (ICP) for atomic emission spectroscopy (AES) is strongly dependent upon the sample introduction system. The Thermospray Vaporizer has recently been shown to yield enhanced sensitivity compared to conventional pneumatic nebulizers when used as a sample introduction source for the ICP. This report is a study of the properties of the aerosols produced by the thermospray. Aerosol particle diameter distributions have been related to droplet size distribution and nebulization efficiencies as a function of the relevant variables of the nebulization system. The results help explain high emission intensities and lower detection limits achieved using the thermospray. The higher efficiencies with thermospray, compared to conventional pneumatic nebulization, also makes the thermospray a prime candidate for sample introduction into molecular gas ICPs.     

New developments in thermospray sample introduction for atomic spectrometry

The status of thermospray sample introduction for analytical atomic spectrometry was last reviewed in 1992. In this review, we summarize developments in this field since that time, including investigations of aerosol generation processes, noise diagnosis and control with inductively coupled plasma-atomic emission or mass spectrometry (ICP-AES/MS), high flow thermospray, the use of dual-stage desolvation systems based on membrane dryers, and the utilization of thermospray with axially viewed ICP-AES. Since a major advantage of methods based on thermospray is improved limits of detection, the emphasis for applications of thermospray with ICP spectrometries remains focused on environmental sample types, particularly with ICP-MS. Relatedly, the use of thermospray as a means for the direct speciation of Se is also under development.     

Behaviour of the thermospray nebulizer as a system for the introduction of organic solutions in flame atomic absorption spectrometry

The results obtained in the evaluation of the thermospray nebulizer for the introduction of organic solutions in atomic spectrometry are described. To this end, the influence of the nebulization variables (i.e., liquid flow, control temperature and inner diameter of the capillary) and of the nature of the solvent on the fraction of solvent vaporized, on the drop size distribution of the primary aerosol, on the rates of analyte and solvent transport to the atomization cell and on the analytical signal has been studied. Experimental fraction of solvent vaporized values obtained under different nebulization conditions are reported for the first time. The results show that the characteristics of the aerosol generated strongly depend on the nebulization variables since they determine the amount of energy available for surface generation. The median of the volume drop size distribution of the primary aerosol decreases when the control temperature or the liquid flow is increased or when the inner diameter of the capillary is decreased. As regards the physical properties of the solvent, the so-called expansion factor (i.e., the volume of vapour produced per unit volume of liquid solvent) is the most influential. Surface tension and viscosity are much less significant here than in ordinary pneumatic nebulization. The volatility of the solvent and the characteristics of the primary aerosol determine the solvent transport efficiency which reaches values close to 100% in many cases. The analytical signal is mainly determined by the analyte transport rate, although a severe negative effect appears which is related to the high solvent load to the flame. Due to this fact, the use of organic solvents instead of water in thermospray nebulization for Flame Atomic Absorption Spectrometry does not provide clear advantages, at least without desolvation. A new modified Nukiyama-Tanasawa equation has been presented and evaluated in order to predict the Sauter mean diameter of the thermal aerosols. The results show that, under the conditions tested, this equation can not be applied to predict the characteristics of the primary aerosols generated with this type of nebulizer.     

Graphite-furnace AAS with ultrasonic nebulization

A technique combining ultrasonic nebulization of solutions and graphite-furnace atomic-absorption spectrometry is described. The analytical possibilities of two different techniques are shown. In one the nebulized samples are continuously introduced into a graphite tube operated at constant temperature, and in the other deposited on the inner wall of the graphite tube and heated discontinuously. The method chosen influences the absorption values for several elements. The sensitivity for determination by continuous sampling lies between the values for the normal electrothermal AAS injection technique and flame AAS. Higher sensitivities are obtained with the deposition technique.     

Ultrasonic nebulization extraction-heating gas flow transfer-headspace single drop microextraction of essential oil from pericarp of Zanthoxylum bungeanum Maxim

The ultrasonic nebulization extraction-heating gas flow transfer coupled with headspace single drop microextraction (UNE-HGFT-HS-SDME) was developed for the extraction of essential oil from Zanthoxylum bungeanum Maxim. The gas chromatography-mass spectrometry was applied to the determination of the constituents in the essential oil. The contents of the constituents from essential oil obtained by the proposed method were found to be more similar to those obtained by hydro-distillation (HD) than those obtained by ultrasonic nebulization extraction coupled with headspace single drop microextraction (UNE-HS-SDME). The heating gas flow was firstly used in the analysis of the essential oil to transfer the analytes from the headspace to the solvent microdrop. The relative standard deviations for determining the five major constituents were in the range from 1.5 to 6.7%. The proposed method is a fast, sensitive, low cost and small sample consumption method for the determination of the volatile and semivolatile constituents in the plant materials.