基于氦离子化气相色谱法测定微量氧、氮的影响因素

探讨氦离子化气相色谱法测定样品中微量氧、氮含量的影响因素。采用控制变量法,对色谱柱温度、进样流量、进样管道环境及极化电压等因素对微量氧、氮测定结果的影响进行讨论和分析。结果表明,当色谱柱温度为25~45℃时,色谱柱对氧、氮吸附量最小;当进样流量不小于70 mL/min时,微量氧、氮测定结果受外界干扰最小;当极化电压为80~160 V时,氧、氮具有最佳的响应值;初次测定样品中微量氧、氮含量时,需使进样管道表面吸附的氧、氮处于饱和状态,以便获得理想的测定结果。讨论的结果可为氦离子化气相色谱法测定相关样品中微量氧、氮含量时提供技术参考。     

二乙基二硫代氨基甲酸钠流动注射萃取分光光度法测定矿石中微量铜的研究

本文对二乙基二硫代氨基甲酸钠(铜试剂)-四氯化碳流动注射莘取分光光度法测定矿石中微量铜进行了研究。与手工萃取法相比,本法最大特点是大量Mn~(2+)无干扰。方法操作简便、快速、可靠、毒性小;进样频率为20次/小时,RSD为3.5％。线性范围为O～1.28μg/ml。方法用于测定矿石中微量铜,结果满意。     

千瓦级微波等离子炬-原子发射光谱(MPT-AES)在油液分析中的应用

采用千瓦级微波等离子炬-原子发射光谱(MPT-AES)装置对油液样品直接雾化进样分析,对直接稀释后的润滑油中8种金属元素进行了检测,并记录了进样时等离子体形貌的变化.结果表明,所有元素的校正曲线线性回归方程的R~2值均优于0. 995,精密度高,检出限接近传统的ICP-AES方法检出结果,为MPT-AES在油液视情维修中的分析监测及在线快速监测奠定了基础.同时还设计了一种油液在线混合进样装置,操作方便、进样量准确,适用于微量样品的采集和直接稀释及进样.     

库仑滴定法测定六氟磷酸锂中微量水分

基于与卡尔-菲休试剂的反应用库仑滴定法测定了六氟磷酸锂中的微量水分.对同一试样的不同进样量(0.5～5.0 mL 共 10 份)按所提出方法对其水分进行了测定,所得结果在26.3～27.9 μg·g-1 之间,平均值为 27.4μg·g-1,相对标准偏差为 0.72%.     

气相色谱-质谱法测定蔬菜中农药残留时不同进样条件对基质效应的影响

研究了气相色谱-质谱法测定蔬菜中农药残留时不同进样条件对基质效应的影响。蔬菜样品经乙腈提取,提取液进行空白基质加标,在气相色谱分离中用HP-5MS石英毛细管柱为固定相,在质谱分析中采用选择离子监测模式。以甲基毒死蜱为内标物。29种农药均表现为基质增强效应,仅12种农药的基质效应在3%~19%之间;当进样口温度和脉冲压力分别设为280℃和275.8kPa时,可分别使22种农药的基质效应值降至2%~20%以内;适当增加进样体积能有效地降低蔬菜基质效应,最佳进样体积为2μL。     

极谱络合吸附催化波测定蔬菜中微量锗

用Ｇｅ（Ⅳ）－连苯三酚－０溴酸钠极谱络合吸附催化波测定蔬菜中微量锗，结果令人满意。同时比较了不同消化处理方法对测定结果的影响，并研究了该极谱波的形成机理。     

用氢化铝锂-气相色谱法分析液体中的微量水

在石油化工产品和有机溶剂的使用中,常常需要分析其中的水含量。文献报导了很多微量水的分析方法,使用较多的有卡尔一费休库伦法,红外光谱法,气相色谱法等,各有特点,并均在不断改进中。气相色谱法分析微量水研究的较多。有两种方式,一为直接进样法,一为转化进样法。直接进样法是利用色谱柱把水和     

安培检测-离子色谱法测定乳品中的微量碘

 用安培检测 离子色谱法检测了乳品中的微量碘。以NaOH作淋洗液 ,直接进样 ,优化了碘的离子色谱分离和测定条件 ,方法的检测限达 1μg/L(3倍信噪比 )。测定了婴儿奶粉、孕产妇专用奶粉和鲜牛奶中的微量碘 ,加标回收率分别为 89 0 % ,86 0 %和 84 1%。     

气相色谱法分析高纯异丁烯中的微量烃类杂质

采用HP Al2O3/S PLOT(50 m×0.32 mm i.d.×8 μ m) 毛细管色谱柱对高纯异丁烯中的微量烃类杂质进行了气相色谱方法研究。结果表明,该色谱柱能很好地分离异丁烯中的C1~C4烃类杂质;采用液相进样阀液态直接进样,保证样品不失真,所测定的结果有良好的准确度和精密度。     

降低二硫化碳萃取液中痕量苯检出下限的气相色谱法

摘要：提出一个直接进样口（岛津WBI-17）和SE-30填充柱测定海水中微量苯的二硫化碳萃取气相色谱分析方法。方法的检测下限低、操作简单、样品用量少、重复性好。     

悬浊液直接进样非火焰原子吸收法测定蔬菜样品中微量铬的研究

本文通过用直接悬浊液进样原子吸收法对新鲜蔬菜中铬的测定,研究了各种实验条件,并建立了实际测定新鲜蔬菜中微量元素的方法。该法将可用于食品。     

Characteristics of the aerosol particulates in the atmosphere in an urban environment at Faisalabad, Pakistan

Summary The deposition of trace and major elements from the atmosphere to the ground is an important factor for plants, animals and humans as well. Total suspended particulate matter was measured by a standard gravimetric technique. A scanning electron microscope was used for the evaluation of the size distribution and morphological structures of the aerosol particulates trapped on the surface of filter paper. The aerosol particulates were studied by a scanning electron microscope at various magnification. The trace elemental composition in the atmosphere of Faisalabad was studied by using instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). Concentrations of 23 trace elements and a major one were determined in samples of aerosol particulates collected during a longe sampling period in the atmosphere at Faisalabad, Pakistan. Their amount was two times higher than the limits adopted by the U.S. Environmental Protection Agency for the urban environment.     

Atomic absorption spectrometry — pregnant again after 45 years

Because atomic absorption spectrometry (AAS) seems to be so simple at first glance, its forthcoming end and replacement by more exciting techniques has been forecasted more than once over the past 45 years. However, AAS has received strong impetus again and again, e.g. by the introduction of the graphite furnace technique, and of flow injection, to mention but a few. Although more and more researchers, and even more instrument manufacturers are turning their back on AAS these days, this author believes that AAS is about to give birth to new offspring in the very near future. The most important ones are solid sampling and speciation analysis on the application side, a much deeper exploitation of the potential of flow injection analysis, the use of diode lasers as radiation sources, and the introduction of continuum-source AAS on the instrumental side. The latter could replace conventional line-source AAS in the foreseeable future because of its obvious advantages in essentially all analytical aspects.     

Atomic absorption spectrometry (AAS) – a versatile and selective detector for trace element speciation

AAS as a highly sensitive and specific single element technique is ideally suited as a detector for speciation analysis. The combinations of chromatographic separation with element specific detectors (flame AAS, electrothermal AAS (ETAAS), hydride generation AAS (HGAAS)) provide powerful approaches to the determination of all species. Sample stabilisation is the area that requires most attention as it still represents the main source of problems encountered in speciation work. The correct speciation depends on how the sample is handled prior to analysis. Unfortunately, no universal procedure has been found. Anything that changes redox conditions, pH or complexation equilibrium is clearly unacceptable.     

Coupling of ultrasonic nebulization to flame furnace atomic absorption spectrometry—new possibilities for trace element determination

The use of ultrasonic nebulization (USN) with desolvation system for sample introduction in flame atomic absorption spectrometry (F AAS) and flame furnace atomic absorption spectrometry (FF AAS) with a nickel tube is described. Polytetrafluorethylene (PTFE) adaptors were built to replace the pneumatic nebulizer for USN-F AAS measurements. For USN-FF AAS analysis, an alumina injector allowed the direct introduction of the dry aerosol into the nickel tube. The analytical performance of both systems is shown for Ag, Bi, Cd, Cr, Cu, Mn, Pb, Sb, Se, Tl and Zn. The results demonstrate that a sensitivity gain of up to 39 times can be achieved using USN-FF AAS, mainly due to the increase in residence time and to the absence of dilution of the analyte by the flame gases, as the atomization takes place inside the nickel tube. However, elements that require higher atomization temperatures, such as Cr and Mn, are more efficiently determined using USN-F AAS. To evaluate the accuracy of the proposed methods for the determination of trace elements, five certified reference samples were analyzed, and good agreement was, in general, achieved between certified and determined values at a 95% confidence level. The relative standard deviation was frequently below 5%, demonstrating good precision, particularly for USN-FF AAS. In this sense, coupling of USN with F AAS and especially with FF AAS has proved to be simple, safe, with high precision and good accuracy, also maintaining some of the most important features of F AAS, such as the high analytical frequency and the low running cost.     

High-resolution continuum source atomic absorption spectrometry: a review of current applications

Atomic absorption spectrometry (AAS) is one of the most widely used and available methods for analysis of substances and materials. It allows one to determine about 70 elements from the periodic table and is characterized by rapidity, high accuracy and sensitivity, as well as simplicity of analytical techniques. A feature of AAS is simultaneous determination of only one element due to the use of a measurement design with a line source (hollow-cathode lamps, high-frequency electrodeless lamps, optical quantum generators, etc.). To make AAS more competitive, the first commercially available continuum source atomic absorption spectrometer was designed in 2004. Unique analytical capabilities of the new instruments found application first of all in the analysis of food, pharmaceuticals, waste and drinking water, oil and petrochemicals, biological objects, etc. This review covers publications on the application of continuum source AAS in analytical chemistry and provides a development outlook of the method.

     

Prospects and problems in absolute analysis by electrothermal atomic absorption spectrometry

The most significant achievements in the development of methods of absolute analysis in electrothermal atomic absorption spectrometry (ET AAS) made in the recent five years are discussed. Problems requiring further investigation and the significance of the concept of absolute analysis in the evolution of ET AAS are pointed out.     

Prospects and problems in absolute analysis by electrothermal atomic absorption spectrometry

The most significant achievements in the development of methods of absolute analysis in electrothermal atomic absorption spectrometry (ET AAS) made in the recent five years are discussed. Problems requiring further investigation and the significance of the concept of absolute analysis in the evolution of ET AAS are pointed out.