Some experiments with an extended torch for the determination of nitrogen in aqueous solution with the aid of ICP-AES

[No abstract available]Articl

Determination of Main and Minor Components of Silicon Based Materials by a Combustion with Elemental Fluorine, Separation of Gaseous Fluorination Products by a Carrier Gas Distillation and Gas Mass Spectrometry.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel

Inductively-coupled plasma atomic emission spectroscopic determination of trace impurities in ZrO2-powder

International audienceFour independent procedures including one using slurry nebulization ICP-AES were developed for the trace analysis of ZrO2 powders. They were evaluated with respect to detection limits, blank values, interferences, accuracy and precision. For the procedures I-III ZrO2 powder was decomposed by fusion with a 10-fold excess of NH4HSO4 and subsequent dissolution of the melt in either water or, after evaporation of NH4HSO4, in diluted HNO3. In procedure I the solution was directly analyzed by ICP-AES, which was optimized with the aid of a simplex algorithm. In procedure II Zr was separated by extraction from 6 mol/l HNO3 with a 0.5 mol/l solution of 2-thenoyltrifluoroacetone (TTA) in xylene. More than 99.5% of the Zr was removed and more than 95% of the trace elements retained. In procedure III the matrix was separated by its precipitation as ZrOCl2·8 H2O from a (1:4) HCl-acetone medium. More than 98% of Zr were removed and more than 90% of the trace elements were retained. In procedure IV the ZrO2 powder was dispersed by ultrasonic treatment in water acidified with HCl (pH 2) and the slurry was directly analyzed by ICP-AES using a Babington nebulizer. The optimization and the analytical features of this procedure will be described in a subsequent paper. In all procedures the calibration was performed by standard addition and matrix matching was not necessary. The detection limits varied from 0.3 ?g/g (Ca) to 10 ?g/g (Al). The standard deviations obtained were 1-10% depending on the element and its concentration in the sample. The results of the procedures for 6 commercially available fine ZrO2 powders were found to agree for Al, Ca, Fe, Mg, Na, Ti and Y. A good agreement between the results of the procedures using matrix separation was also observed for Cu, Mn, V, but the concentrations of these elements found by methods without matrix separation were considerably higher. Except for Ca and Mg the blank values encountered were below the detection limits. © 1992 Springer-Verlag

Optimization of slurry nebulization inductively-coupled plasma atomic emission spectrometry for the analysis of ZrO2-powder

International audienceThe optimization and use of ICP-AES with slurry nebulization for the direct analysis of ZrO2-powder is described. The powder samples are dispersed in water, acidified to pH 2 and the slurry is fed into a Babington nebulizer. The effects of grain size, pH of the suspending medium and standing time on the stability of the slurry are discussed. For the optimization of the ICP operating conditions, a simplex technique is applied and for this purpose three types of objective functions were examined. Identical behaviour of slurries and solutions with the same matrix concentrations in the ICP-AES is achieved for powders with particle sizes lower than 10 ?m; in the latter case calibration can be performed by standard addition with aqueous solutions. The detection limits for Al, B, Ca, Cu, Fe, Mg, Mn, Na, Ti, V. Y are 0.03 ?g/g to 10 ?g/g and the standard deviation is generally lower than 10%. Six commercially available ZrO2 powders are analyzed by slurry nebulization ICP-AES and the results were found to agree well with those obtained by ICP-AES after chemical decomposition of the samples. © 1992 Springer-Verlag

Photographic plasma images and electron number density as well as electron temperature mappings of a plasma sustained with a modified argon microwave plasma torch (MPT) measured by spatially resolved Thomson scattering

In this work the determination of electron number densities and electron temperatures for the case of a modified microwave plasma torch (MPT) operated at 100 W with argon by means of spatially resolved Thomson scattering measurements and photographic records of the MPT at different working conditions are reported. With an internal gas flow of 500 ml min-1 and an outer gas flow of 200 ml min-1 electron number densities and electron temperatures are in the range of 1020 m-3 to 1021 m-3 and of 16 000–18 000 K, respectively. When increasing the internal gas flow from 500 to 900 ml min-1 the plasma becomes longer and the maximum electron number density increases by a factor of 2. An increase of the outer gas flow from 200 to 700 ml min-1 leads to a lifting of the whole plasma from the burner edge with the maximum electron number density remaining unchanged. An increase of the power from 80 to 180 W was found to lead to higher electron number densities whereas the electron temperatures remain unchanged. The addition of 1.2 mg min-1 of water vapor to the internal gas flow leads to a decrease of the electron number density from 4.7×1020 m-3 to 2×1020 m-3 and to an increase of the electron temperature from 16 000 to 22 000 K. In order to document the influence of the internal gas flow rate, water introduction and introduction of easily ionized elements on the visible plasma shape digitally recorded photos of the plasma are presented