Evaluation of Microwave Plasma Torch (MPT) as an Excitation Source for Determination of Mercury

The microwave plasma atomic spectrometry is an important branch of the plasma atomic spectrometry. Since the first use of microwave induced plasma（MIP） as an excitation source for spectral Chemical analysis by Broida and Chapmanin in 1958, especially the introduction of TM;cavity by Beenakker in 1976 and of surfatron by Moisan in 1979 with which an atmospheric pressure helium MIP could be obtained, MIP has received considerable attention as a new excitation source for spectrometric analysis. However, since MIP suffers from the in ability to analyse the aqueous sam-

Studies on Excitation and Rotational Temperatures of an Oxygen-shielded Argon Microwave Plasma Torch Source

Excitation（ Texc ） and rotation（ Trot ） temperatures were determined under different conditions for an oxygen-shielded argon microwave plasmsa torch source（OS-Ar-MPT）. The Texc value, which was shown to be between 4300 and 5250 K under different operating conditions, was calculated from the slope of the Boltzmann plot with Fe as the thermometric species. The Trot value, which was in the range of 2100-2500 K, was measured with OH molecular spectra. The influences of microwave power, flow rates of the support gas, cartier gas, and shielding gas, as well as the observation height on Texc and Trot were investigated and discussed. The detailed results of Texc and Trot provided a better understanding of the performance of an OS-ArMPT as a source for atomic emission spectrometry.

Study of Spectral Character of Alkali Metals Using Microwave Plasma Torch Simultaneous Spectrometer

A microwave plasma torch （MPT） simultaneous spectrometer was used to study the spectral character and the matrix effect on alkali metal ions in solution. The main parameters were optimized. The microwave forward power was 100 W. The argon flow rate that was used to sustain the Ar-MPT included the flow rate of carrier gas and the flow rate of support gas, which were 0. 8 and 1.0 L/min, respectively. The HC1 concentration in the solution was 0.02 mol/L. The observation height was 9. 0 ram. The detection limits of Li, Na, K, Rb, and Cs were 0. 0003, 0. 0004, 0. 009, 0.07 and 2.4 mg/L, respectively, and the resuhs obtained by the Ar-MPT were compared with those obtained by argon inductively coupled plasma（Ar-ICP） and argon microwave induced plasma（Ar-MIP）. The interference effects of several matrix elements were also studied.

Use of a Microwave Plasma Process at Atmospheric Pressure for Bacterial Inactivation without Thermal Effects

An atmospheric microwave plasma argon was used for the inactivation of bacteria E. coli. The employed device, called Axial Injection Torch (or TIA for Torche à Injection Axiale), consisted of a microwave power source, a waveguide and a gas supply system. Using this argon plasma source, we studied the effects of the exposure time, the exposure distance, the input power, and the gas flow rate on the reduction rate of Escherichia coli cells. The first part of the study was carried out with a static sample exposed to the plasma and then in the second part the sample was set in motion relative to the plasma jet. A log reduction number of E. coli of 4 (10-4 CFU/mL) was obtained with UV and active species, for UV only a log of 1 (10-1 CFU/mL) was obtained.

Characteristics of Analyte Ionization in Low Power Microwave Plasma Torch

The ionization characteristics of the analytes in a low power Ar microwave plasma torch (MPT) was studied. The influence of forward microwave power, the flow rate of carrier gas and matrix element on the degree of ionization were observed. The axial profiles of the degree of the ionization of some elements were determined. The experimental results are very important for developing the new analytical source——microwave plasma torch (MPT).

Evaluation of Improved Ultrasonic Nebulizer for Miniature Simultaneous Microwave Plasma Torch Spectrometer

A new automatic sample solution introduction system for miniature simultaneous microwave plasma torch（MPT） atomic emission spectrometer was developed. The operating parameters were optimized. The detection limits of the spectrometer with an ultrasonic nebulizer for Ag, Al, Ba, Ca, Cr, Cu, Fe, Mg, Mn, Sr, and V are 5-10 times lower than those obtained with a pneumatic nebulizer and are also lower than those obtained by a Model JX-lOlO MPT spectrometer. Two practical samples were analyzed to test the reliability and sensitivity of the system.

Determination of Carbon by Means of Microwave Plasma Torch Atomic Emission Spectrometry

The determination of carbon by means of microwave plasma torch atomic emission spectrometry(MPT-AES) was studied. Aqueous samples were introduced with a pneumatic nebulization system. The detection limit for carbon was 0. 047μg/mL.The method was applied to the analysis for tap water and results were satisfactory.

Determination of Cd,Pb and Sr by Microwave Plasma Torch Atomic Emision Spectrometry Using an Electrothermal Vaporization Sample Introduction System

A method for the determination of Cd,Pb and Sr by microwave plasma torch(MPT)atomic emission spectrometry(AES)was developed.Th e samples were introduced into the MPT with an elec trothermal vaporization(ETV)device.The effects of some experimental conditions on the de-termination of Cd,Pb and Sr were examined.The effects of easily ionized elements on the emis-sion intensity of Cd,Pb and Sr were studied in detail.The detection limits for Cd,Pb and Sr are 2.4,4.0 and 1.3 ng/mL,respectively.

Studies on Combination of Flow Injection and Microwave Plasma Torch-Atomic Emission Spectrometry

Although the flow injection(FI) as a sample introduction technique has been extensively applied to atomic spectrometry, such as ICP-AES and AAS, very little has been done so far on coupling FI to microwave plasma systems. Gehlausen et al. determined aqueous fluorine by coupling flow injection analysis (FIA) with HeMIP

EVALUATON OF MICROWAVE PLASMA TORCH FOR ATOMIC FLUORESCENCE SPECTROMETRY WITH AN ULTRASONIC NEBULIZATION SAMPLE INTRODUCTION SYSTEM

In this paper, a new MPT(microwave plasma torch) device has been used as a atomizer for atomic fluorescence spectrometry. Spme elements, such as Zn, Cd, Hg, Pb, As, Co, Mg, Cu, Ag, Mn, Fe have been investigated in detail.

Determination of Elements of Groups Ⅲ A and ⅣA Using Microwave Plasma Torch Atomic Emission Spectrometry

The determination of the elements of groups ⅢA and ⅣA by means of microwave plasma torch atomic emission spectrometry(MPT AES) was studied systematically. Sample solutions were introduced into the plasma with a pneumatic nebulizer in continuous sampling mode and flow injection (FI) mode. The emission characteristics of these elements were investigated in details, and the basic data obtained are very important to the development of MPT AES. The analytical performances were examined. For most elements, the detection limits obtained by this method were principally the same as those obtained by inductively coupled plasma atomic emission spectrometry (ICP AES).

On Line Anion Exchange Preconcentration in Microwave Plasma Torch Atomic Emission Spectrometry

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Study of Gas Heating by a Microwave Plasma Torch

Among the different types of microwave plasma torches, the axial injection torch (TIA) has been used for several years to create chemically active species, in applications such as gas analysis, surface processing and gaseous waste treatments. The TIA allows the coupling of microwave energy (2.45 GHz) to a gas injected axially at the nozzle’s exit. The TIA produces non-local thermodynamic equilibrium plasmas with a high luminosity and a maximum density of charged particles at the nozzle’s exit. The present work is dedicated to study the plasma created by a TIA, running at atmospheric pressure. The study involves both experiment and modeling of this torch, in order to maximize the coupling between the microwave power and the plasma and to define the optimum plasma and flow operating conditions for plasma-to-gas heat transfer.

Synthesis of SiOx Nano-Powders Using a Microwave Plasma Torch at Atmospheric Pressure

The silicon oxide nano-powders (SiOx-NPs) were obtained in an atmospheric microwave plasma torch using a gas-phase silicon tetrachloride (SiCl4) with N2 and H2. The gas-phase SiCl4 was injected with H2 gas into the microwave plasma torch generated by N2 and air swirl gas, and then the dark brown powders were deposited on the inner wall of a quartz tube. The sample was analyzed by an X-ray photoelectron spectroscopy (XPS), a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS), and an X-ray diffraction (XRD). The average size and oxidation x values of synthesized SiOx-NPs were approximately 230 nm and 0.91, respectively. Furthermore, the volumetric charge capacity is 1127 mAh/g and has 89.2% retention after 100 cycles.

In Situ Analysis of Tobacco Leaves Based on Microwave Plasma Torch Desorption Ionization Mass Spectrometry

Tobacco is an important economic crop worldwide.Tobacco leaves contain a large number of natural products.Therefore,the analysis of tobacco composition is crucial for the control of tobacco safety and quality assessment.Microwave plasma torch desorption ionization mass spectrometry(MPT-MS) is an emerging ambient mass spectrometry(AMS) technique that can be used for rapid real-time analysis of s amples without pretreatment.Our work focuses on the chemical composition analysis of tobacco using MPT-MS,and 14 compounds were detected in green flue-cured tobacco leaves,while 30 compounds were detected in cured flue-cured tobacco leaves,which confirms that curing can enhance the flavor of cigarettes.Furthermore,we successfully in situ identified characteristic fragment ions of α/β-CBD(α/β-cembranoids),an important aroma compound in tobacco by MPT-MS.The results demonstrate the capability of MPT-MS for in situ analysis of tobacco components and its potential for evaluating tobacco quality.

微波消解MPT-AES测定催化剂中的铈

研究了微波等离子体炬原子发射光谱法(MPT AES)测定催化剂中稀土元素铈的方法。详细考察了测定铈时的实验参数,进行了系统优化。催化剂处理采用了微波消解技术。方法的检出限为2.56μg/mL,相对标准偏差(n=11)为4.37%,线性范围为20～250μg/mL,回收率在90%～110%之间。实验结果表明微波消解和MPT AES联用可成为测定催化剂中铈含量的简单、快速、准确的分析方法。

MPT-AES测定矿泉水中的Ca、Mg和Na

用微波等离子体炬 (MPT)为激发光源 ,氩气为等离子体工作气体 ,用气动雾化进样 ,采用标准加入法研究了微波等离子体炬原子发射光谱法 (MPT -AES)测定矿泉水中Ca、Mg和Na的方法。详细考察了溶液中盐酸浓度、微波前向功率、载气流量、工作气流量、氧屏蔽气流量等实验参数对测定的影响 ,同时考察了易电离元素 (EIE)钾和钠对钙和镁发射强度的影响。结果表明 ,MPT -AES测定矿泉水中的Ca、Mg和Na操作简便 ,自动化程度高 ,运转费用低 ,准确快速 。

微波消解-MPT-AES法测定海带中钙和锌

分别使用常规消解方法与微波消解方法处理海带样品,采用微波等离子体炬原子发射光谱法(MPT-AES)测定海带中钙和锌的含量.详细考察了分析谱线、微波前向功率、载气流量、工作气流量等实验参数对元素测定的影响.在最佳实验条件下测得钙和锌的检出限分别为3.5×10-3,4.62×10-2μg/mL;线性范围分别为0.04～4.00μg/mL和0.04～10.00μg/mL;精密度分别为0.76%和0.91%;加标回收率分别在98.5%～106.2%和97.8%～104.8%.结果表明,微波消解方法与常规消解方法相比精密度与准确度均较高,微波消解-微波等离子体炬原子发射光谱法是一种简便、快速、准确、无污染的绿色环保方法.

气动雾化进样微波等离子体炬(MPT)原子荧光光谱法测定锌的研究

本文将水溶液雾化进样与微波等离子体炬原子荧光光谱法联用,建立了HCL-MPT-AFS测定Zn的新方法。讨论了实验条件的选择问题以及溶液中共存离子对测定Zn的影响,本文所推荐的方法具有较高的灵敏度和精密度,并将其用于实际样品分析。

微波消解-MPT-AES法测定豆制品中的Cu、Fe、Ni、Cd

研究了用微波消解-微波等离子体炬原子发射光谱法(MPT-AES)测定豆制品中的Cu、Fe、Ni、Cd元素的方法.考察了各微量元素的分析谱线波长、载气流量、工作气流量、氧屏蔽气压力和微波前向功率对Cu、Fe、Ni、Cd元素的发射强度的影响,分析了酸浓度及共存离子对其测定的影响,得到了测量不同金属离子的最佳工作条件,进而得出了在最佳条件下测量Cu、Fe、Ni、Cd元素的检出限(分别为8.28 ng·mL-1、18.96 ng·mL-1、2.77 ng·mL-1、3.19 ng·mL-1)、精密度(分别为1.46%、3.65%、2.30%、1.62%)、回收率(98.97%～101.29%)等,并通过加标回收试验验证了方法的准确性.