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The dispersive effect of polyacrylate amine (NH4PAA) upon suspensions of silicon nitride (Si3N4) is considered. Slurry introduction for axial inductively coupled plasma optical emission spectrometry determination of Al, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni and Ti in powdered Si3N4 has also been investigated. Characterization by zeta potential measurement and slurry stability measurements shows that NH4PAA is a good dispersant for the preparation of Si3N4 suspensions. The optimal concentration of NH4PAA was 0.8 wt% for μm-sized Si3N4 and 1.2 wt% for nm-sized Si3N4. The analytical results obtained using nm- and μm-sized Si3N4 by slurry introduction were in good accordance with results obtained by the high-pressure acid deposition method, thus verifying that calibration curves could be established using aqueous standards. By introducing a low amount of contamination in the sample preparation, an accurate result is obtained for the detection of contamination-risk elements such as K and Na, which cannot be accurately determined by the high-pressure acid deposition method. The limits of detection, which are in the range of 8–250 ng g−1, were shown to be superior to those of the conventional nebulization technique with ICP-OES or ICP-MS.

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-mu m 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 mu m 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. (c) 2006 Elsevier B.V. All rights reserved.

A method of slurry nebulization for inductively coupled plasma optical emission spectrometry (ICP-OES) applied to the analysis of titanium niride(TiN) was reported. The TiN slurry sample was prepared with adding dispersant polyacrylate amine or polyethylene imine for the stabilization and homogenization of suspension, and the amount of additives was optimized. A Babington type cross-flow nebulizer with V-groove was used for nebulization of the slurry for avoidance of blockage from the particles. The stability of slun-y was characterized via zeta potential measurement, scanning electron microscope observation, particle size distrbution measurement and signal stability testing. For nm size TiN, calibration curves could be established by aqueous standards and the analytical results were in good accordance with the alkaline fusion method. For μ m size TiN, a negative deviation was observed for most of elements and this deviation can be corrected by using Ti intrinsic internal standard method. © 2005 Elsevier B.V. All rights reserved.

A fully alkaline procedure, including alkaline fusion, pre-reduction of Se(VI) to Se(IV) in alkaline medium and an alkaline mode of H2Se generation, together with ICP-AES for the determination of total Se in biological and environmental samples, is described. Alkaline fusion coupled with alkaline mode hydride generation could effectively avoid volatile losses of selenium by changing it into soluble salts such as selenate or selenite and greatly eliminate the chemical interference from the co-existing transition metals Fe, Cu, and Mn. The method was verified with a certified reference material and was successfully applied to several real samples such as selenium-enriched plasma, egg, animal feeds and soils with satisfactory results.

A high-concentration with low viscosity ceramic silicon carbide (SiC) slurry prepared for ICP-OES determination of ultra-trace impurities is described in this paper. Good fluidity can be kept up to the slurry concentration as high as 30% (m v−1) by adding 2% polyethylene imine (PEI) as a dispersant at pH 4.0. Stability of the high content slurry of nm-size SiC is characterized by zeta potential measurement and viscosity measurement, and medium pH is experimentally optimized. The analysis can be calibrated using simple aqueous standards in case a high-concentration slurry is nebulized. Owing to extremely low blanks and unusually highly slurry concentration (20% m v−1), extraordinarily low limits of detection ranging from 2 (Mn, Ti) to 100 (Al) ng g−1 could be achieved.

A simple, rapid and reliable method for the determination of Al, Ca, Cr, Cu, Fe, Mg, Mn, Na, Ni, Si, Ti, V and Zr in high purity boron carbide (B4C) using slurry introduction axial viewed inductively coupled plasma optical emission spectrometry (ICP-OES) is described. The sample slurry was prepared by directly dispersing the powdery boron carbide in an aqueous solution without dispersant addition. The accuracy was verified by comparison of the results with those obtained by various other methods and the value of certified reference material ERM-ED 102 (boron carbide powder). Owing to a rather low contamination in the sample preparation and stability of the slurry, the LODs, which were in the range of 0.02–2 µg g−1, were superior to those of the conventional nebulization ICP-OES technique or solid dc-OES.

Characterization of the stability of ceramic suspension for slurry introduction in inductively coupled plasma optical emission spectrometry (ICP-OES) and its application to the analysis of aluminium nitride (AlN) was reported in this paper. Stability and homogeneity suspensions of μm sized AlN and nm sized AlN, as the representatives selected, were characterized by sedimentation test, scanning electron microscope observation and zeta potential measurement. The zeta potential of the interface between the particle and the medium can be controlled by pH adjustment and adding 0.8 wt% polyethylene imine (PEI) for μm size AlN or 2.0 wt% PEI for nm size AlN, respectively. The analytical results obtained via slurry introduction were compared with those via nebulization of aqueous solutions prepared by fusion digestion. The nm size AlN can be directly analyzed by using slurry nebulization ICP-OES with aqueous standards calibration, and the impurities Cu, Fe, Mg, Mn, etc. in μm size AlN can also be determined by slurry method, but the results of some elements with high boiling points, such as Si, Y, etc., show deviation from the reference values.

A slurry sample introduction technique for the analysis of TiO2 powders by axial viewing ICP-OES is reported. Relationships between stable slurries and the conditions, such as particle size, pH, dispersant and its amount, were experimentally investigated. Slurries were prepared by mixing the TiO2 powder with the dispersant poly(acrylate amine) (NH4PAA) and agitation in an ultrasonic bath to ensure good dispersion. The pH of the medium and amount of dispersant has been optimized. Impurities in TiO2 were determined by an axial viewing ICP-OES spectrometer. As representatives, a Standard Reference Material 154 b of µm particle size TiO2 and a nm particle size TiO2 were selected and determined for micro and trace impurities. Analytical results obtained via slurry sample introduction were compared with those via nebulization of aqueous solutions prepared by acid digestion and fusion digestion. The determined results by slurry introduction were in good accordance with the stated values, which verified that the calibration curves could be established by aqueous standards.