Model and experimental investigations of aluminum oxide slurry transportation and vaporization behavior for nebulization inductively coupled plasma optical emission spectrometry.

We analyzed aluminum oxide (Al2O3) by slurry introduction inductively coupled plasma (ICP) optical emission spectrometry through modeling and experimentation. We also studied the relationship between the ICP nebulizer gas flow, the spray chamber geometry, and the particle size of Al2O3 in an attempt to minimize the need for correction factors by ensuring an efficient aerosol mass transport. A cut-off point for the particle size was implemented at approximately 7-10 µm for the sample introduction system. Based on modeling using a customized computer model and some experimental evidences, the maximum particle size for complete vaporization is approximately 7 µm. For a gas flow of 0.8 Lmin(-1), particles with a diameter of up to 8 µm can be evaporated with an efficiency of 68% and particles as large as 5 µm can be evaporated completely within the nebulization gas flow region. The Al2O3 sintering block was ground using a self-made alumina mortar combined with a mixer mill device for particle reduction. The sample slurry was prepared by directly dispersing powdered Al2O3 in an aqueous solution with an addition of 0.5 wt% poly (acrylate amine) (NH4PAA) as the dispersant. The accuracy of the results was compared with the data obtained through high-pressure digestion with acid and with the value of a certified reference material, NIST SRM 699 alumina.

[Direct determination of copper, iron and sodium in high-purity alumina by slurry introduction furnace atomic absorption spectrometry with Smith-Hieftje background correction].

Direct determination of copper, iron and sodium in high-purity alumina was performed by slurry-furnace atomic absorption spectrometry with Smith-Hieftje background correction (S-H-GFAAS). Instrument conditions of GFAAS such as pyrolysis, atomization and hollow cathode lamp current by S-H background correction were optimized, and the optimal experimental conditions were selected. Calibration was performed using aqueous standards method for sample analysis. The accuracy of the proposed method was shown for the case of Al2O3 (AKP-30), and compared with those obtained by furnace atomic absorption spectrometry subsequent to decomposition by sulfuric acid in PTFE pressure vessels. The results were in agreement well with values found in the literature by different methods. It is a simple, convenient and accurate method and it is suitable for the rapid analysis of trace element in alumina. The linear regression coefficients of the calibration curves were better than 0.999 0. The detection limits were 0.66, 2.5 and 0.13 ng x g(-1), respectively, with a relative standard deviation being not more than 5.2%.

[Research advance in slurry introduction for graphite furnace atomic absorption spectrometry].

Slurry introduction graphite furnace atomic absorption spectrometry combining the significant advantages of the solid and liquid sampling methods is already considered as a mature technique. It was widely utilized for metal determination in trace and even ultra trace analysis in organic and inorganic complicated matrix, even for routine analysis. Methodology of the analysis of various materials using slurry furnace atomic absorption spectrometry was reviewed in the present paper in late 10 years. Techniques of slurry preparation (liquid media, stabilizing agents, mass/volume ratio, particle size and slurry homogenization systems), the chemical modification, background correctors, calibration, precision and trueness of analysis were described in detail. The developing trend has also presented. Eighty one references were cited.

[The application of inductively coupled plasma atomic emission spectrometry/mass spectrometry to the analysis of advanced ceramic materials].

Advanced ceramics have been applied to various important fields such as information science, aeronautics and astronautics, and life sciences. However, the optics and electric properties of ceramics are significantly affected by the micro and trace impurities existing in the material even at very low concentration level. Thus, the accurate determination of impurities is important for materials preparation and performance. Methodology of the analysis of advanced ceramic materials using ICP-AES/MS was reviewed in the present paper for the past decade. Various techniques of sample introduction, especially advances in the authors' recent work, are described in detail. The developing trend is also presented. Sixty references are cited.

[Study of fundamental parameters of inductively coupled plasma for slurry nebulization--electron density determination].

The electron density of the plasma for slurry nebulization inductively coupled plasma emission spectrometry was determined and reported in the present paper. The Stark broadening method of Hg line (486.1 nm) was chosen and used to determine the electron density of the plasma for nebulization into the inductively coupled plasma with both the aqueous solution and different concentration titanium slurry. There are approximately the same plasma electron density results of 10(15) cm(-3) for the two nebulization ways. The experiment verified that the plasma electron density only shows a litter decrease with 10% TiO2 suspension nebulization into the inductively coupled plasma. This means that the plasma electron density does not change remarkably with high content suspension nebulization into the inductively coupled plasma emission spectrometry instrument. It will help trace elements determination by using high concentration suspension nebulization into the inductively coupled plasma emission spectrometry instrument.

[Study of fundamental parameters of inductively coupled plasma with slurry nebulization--I. Excitation temperature determination].

The excitation temperature of plasma with slurry nebulization into inductively coupled plasma emission spectrometry was determined and reported in the present paper. Ti-lines and multi spectrum lines method were chosen and used to determine the excitation temperature with nebulization into the inductively coupled plasma with both aqueous solution and 0.05% titanium slurry. There were approximately the same plasma excitation temperatures of 5 000-6 000 K for the two nebulization ways. The experiment verified that the excitation temperature only showed a little increase with RF power increasing. This means that the atomization efficiency did not change remarkably with slurry nebulization into the inductively coupled plasma if only the RF power was increased. Therefore, the analytical results were not much improved in the inductively coupled plasma emission spectrometry with slurry nebulization when only changing RF power.

[Research advance in slurry sample introduction for plasma emission spectrometry/mass spectrometry].

The present review is focused on the advances and applications of slurry introduction for plasma spectrometry/mass spectrometry. Preparation and characterization of the suspensions are described, including the methods for decreasing the particle size such as the bottle and bead method, mixing mill method, vibration mill method, and supersonic mill method. Dispersion of the particles can be controlled via adding dispersant and pH adjustment. Some methods for particle size measurement, namely, sedimentation, optical microscopy, photosedimentometry, laser diffraction, scanning electron microscopy and transmission electron microscopy, are also described. Effects of suspension concentration and calibration techniques, including calibration by simple aqueous standard, internal standard, correction by empirical correction factors, standard additions, intrinsic internal standardization, and standard slurries, are discussed. Fundamental study of slurry introduction and its applications to plasma spectrometry/mass spectrometry are reviewed.

Direct determination of impurities in high purity silicon carbide by inductively coupled plasma optical emission spectrometry using slurry nebulization technique.

A novel method for the determination of Al, Ca, Cr, Cu, Fe, Mg, Mn, Ni and Ti in high purity silicon carbide (SiC) using slurry introduction axial viewed inductively coupled plasma optical emission spectrometry (ICP-OES) was described. The various sizes of SiC slurry were dispersed by adding dispersant polyethylene imine (PEI). The stability of slurry was characterized by zeta potential measurement, SEM observation and signal stability testing. The optimal concentration of PEI was found to be 0.5 wt% for the SiC slurry. Analytical results of sub-mum size SiC by the slurry introduction were in good accordance with those by the alkaline fusion method which verified that determination could be calibrated by aqueous standards. For mum size SiC, results of most elements have a negative deviation and should be calibrated by the Certified Reference Material slurry. Owing to a rather low contamination in the sample preparation and stability of the slurry, the limits of detection (LODs), which are in the range of 40-2000 ng g(-1), superior to those of the conventional nebulization technique by ICP-OES or ICP-MS.

[Non-nascent hydrogen mechanism of plumbane generation].

The mechanism of plumbane generation in dichromate system was studied via investigation of the relationship between the plumbane yield and the molar number of the reactants. A flow injection hydride generator was used in the study. Reactant moler number was calculated by the injected volume and the reactant concentration, and the plumbane yield was measured via an AAS spectrometer equipped with an electrothermal quartz tube atomizer. Experimental results show that the acid was first used for the neutralization of NaOH and successively participated in the redox reaction of borohydride with dichromate with a constant molar ratio of 9.95 +/- 0.42 (expressed in terms of mean +/- standard deviation). At the same time, plumbane generation was displayed as synchronously taking place with the redox reaction, and the yield increased with the increase of acid. The mechanism of plumbane generation was thus deduced as an induced reaction or a catalytic reaction by the redox reaction. Up to this end, the non-nascent hydrogen mechanism of hydride generation has been verified for all the IVA elements.