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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 47 (1975), S. 188-189 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' journal of analytical chemistry 359 (1997), S. 317-325 
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The progress possible in the analysis of refractory powders such as ZrO2, SiC and Al2O3 by the use of new sample preparation, processing and introduction techniques elaborated for AAS, ICP-OES and ICP-MS with low and high mass resolution is demonstrated. For optimized sample preparation techniques based on dissolution of ZrO2, e.g. fusion with (NH4)2SO4, it is shown to what extent impurities present in (NH4)2SO4 determine the detection limit. Hydraulic high pressure nebulization with and without matrix removal by complexing the impurities with dithiocarbamates (Cu, Co, Cr and Ni) or oxine (Fe, Mn and Mo) and fixing them on a C18 solid phase for subsequent solid phase extraction coupled with flame atomic absorption was used to determine Fe, Cu, Cr, Mn, Ni, Co and Mo impurities in (NH4)2SO4 in the 10–100 ng/g range. Further a method to synthesize (NH4)2SO4 with higher purity than some commercially available high-purity (NH4)2SO4 with respect to Fe, Cu, Cr and Mn using high-purity NH3 and chlorosulphonic acid is shown. Reliable determinations of Fe and Al at the 100 μg/g level in ZrO2 with ICP-OES with matrix removal as well as with ICP-MS without matrix removal are reported. For the direct analysis of Al2O3 powders, slurry nebulization ICP-MS sample introduction is shown to improve detection limits and to reduce sample preparation, if the leachable and non-leachable fractions are analyzed separately. For powders such as SiC, the matrix or solvents can cause spectral interferences. Matrix removal is shown to be useful to improve detection limits for the interfered elements. High resolution ICP-MS can be used to control the completeness of matrix removal techniques and to overcome limitations due to spectral interferences even in case of complex materials.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' journal of analytical chemistry 358 (1997), S. 214-217 
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Radio-frequency glow discharge mass spectrometry (RF GDMS) has been applied to the determination of trace elements in ceramic perovskite layers (La0.65Sr0.3MnO3) using synthetic standards. For the preparation of these standards high-purity powder of the basic material (La0.65Sr0.3MnO3) was doped with trace elements in concentrations from 20 to 500 μg/g and the mixture was pressed to compact samples. The resulting calibration curves and the calculated relative sensitivity factors (RSF) differed only from 0.4 to 2 for different elements. For nearly all elements the standard deviations in the determination of trace elements in La0.65Sr0.3MnO3 were better than 15% and detection limits (using the 3σ-criterion) were below 10 μg/g. Changes of the discharge parameters (RF power, pressure of the discharge gas (Ar) in the RF glow discharge) have no significant influence on the sensitivity to elements.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An extraction procedure for the determination of soluble and insoluble nickel and its compounds in ambient air dust was investigated employing a special device for the generation of test aerosols and using water-soluble NiCl2, partly water-soluble NiCO3 and water-insoluble NiO as model compounds. Additionally, results of the separation and determination of different nickel species down to some ng/m3 in ambient aerosols are discussed. The extraction was carried out with a solution containing 0.01 mol/L EDTA in order to determine partly water-soluble compounds such as NiCO3 and water-soluble, non-toxic nickel compounds in one step. Airborne dust was sampled on filters at locations close to two metallurgical plants in Northrhine-Westphalia (Germany), and first results on the nickel concentration (mean (median) values over a period of 4 months: 8.6 ± 6.5 ng/m3 (6.7 ng/m3) and 27.7 ± 36 ng/m3 (10.8 ng/m3), respectively) in the collected dust are presented. For EDTA-soluble nickel compounds the maximum and mean fractions of total nickel were found to be 77.1% and 18.6 ± 12%, respectively.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A comparative study was performed of 600 W capacitively coupled microwave plasmas (CMP) with different plasma gases (Ar, N2 and air) and aerosol generation with the aid of a Légère pneumatic nebulizer. Detection limits with the different working gases are in the order of 15–4000 ng/mL for Fe, Cr, Zn, Mg and Ca in aqueous solutions. The influence of organic solutions on the stability of the plasma is discussed. The determination of Co, Cr, Fe, Mg and Ni in different oil samples by OES is described, using an air-CMP and pneumatic nebulization after dilution of the oils by 20% with cyclohexane. The detection limits for these elements are in the 100–400 ng/g range. Results obtained for a waste motor oil for the elements mentioned in the concentration range of 4–50 μg/g were found to be in good agreement with those obtained by ICP-OES after digestion of the oils at high pressure in PTFE vessels.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' journal of analytical chemistry 361 (1998), S. 582-584 
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Combustion with elemental fluorine has been used for the decomposition of ceramic powders of Si3N4, SiC and BN. Volatile reaction products like N2, BF3, SiF4 and various fluorides of carbon are detected on-line with a quadrupole mass spectrometer. It is shown that thermal separation of the combustion products by controlled release from a cooling trap is useful to decrease limitations by isobaric interferences in quadrupole mass spectrometry. The developed fluorine combustion coupled to a mass spectrometry procedure has been used for the determination of the stoichiometry of Si3N4 in which Si could be directly determined.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The suitability of eleven modifiers (Pd-, Mg-, K-, Ca- and NH4-salts) for electrothermal vaporization coupled to inductively coupled plasma mass spectrometry (ETV-ICP-MS) for the determination of Mn, Cu, Zn, Cd and Pb has been studied. Solutions containing varying quantities (10–2000 ng absolute) of these salts have been added to four different amounts of analyte to study their suitability as modifier and their mass dependent influence. The best sensitivity enhancement for all elements tested was achieved with IrCl3 and PdCl2. From a comparison of the effect of PdCl2 vs. Pd(NO3)2 it could be concluded that the mechanism of matrix modification also depends on the chemical form of the modifier. Particularly, for the volatile elements Cd and Zn differences in the behavior of the different chemical compounds of one metal (e.g. Pd) is evident, which shows that the enhancement effect is a result of the stabilization of the analytes in the graphite tube prior to vaporization and the improvement of the transport efficiency after vaporization.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A simple and rapid procedure for the calibrationless determination of trace concentrations of As(III) and total As in contaminated water samples is presented. Arsenic is preconcentrated as As(III) in a flow-through cell with a gold plated porous electrode and is then stripped anodically by a constant current. The stripping chronopotentiogram is registered and evaluated. The As concentration is calculated directly from the combined Faraday’s laws. The total As content was determined after converting all As species to As(III) by microwave-assisted reduction with hydrazine hydrochloride in a closed vessel. The detection limit was found to be 0.15 μg/L and the linear response range was 0.5 to 10 000 μg/L. Tap water, surface water, and waste water samples were analyzed.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' journal of analytical chemistry 363 (1999), S. 145-155 
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The scope of a number of plasma spectrochemical methods for the determination of the main components and impurities in ceramic powders is described. These methods meet the requirements for the analytical characterization of new structural and functional ceramics for modern industrial applications and electronic devices. For ceramic powders, spectrochemical analysis with direct methods as well as analysis subsequent to sample dissolution are discussed. Fusion is a powerful method for the dissolution of ZrO2 ceramic powders, provided the fluxes are pure enough. For determinations in Al2O3, SiC and ZrO2, it will be shown that ICP-MS is very useful. This is especially true for trace analysis after matrix removal. The latter can easily be performed on-line in the case of the analysis of Al2O3 powders. For direct analysis of ceramic powders, the direct insertion of samples into the plasma, spark and arc ablation, laser ablation, electrothermal vaporization and slurry nebulization are discussed. Particular attention is given to the direct analysis of ceramics in powder form (Al2O3, SiC, Si3N4, B4, WC) using ICP-OES with slurry nebulization as well as with direct sample insertion (DSI) and with electrothermal vaporization (ETV). For the two latter methods, the use of chemical modifiers for volatile compound formation will be shown to be of great importance, and its features will be explained using thermochemical considerations.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' journal of analytical chemistry 368 (2000), S. 15-22 
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The state-of-the art and trends of development in ICP-MS are presented. Special reference is made to progress in plasma sources, which can be used as ion sources and, especially, the inductively coupled plasma and new microwave plasma sources. Further, progress in sample introduction for plasma mass spectrometry is discussed with special reference to new pneumatic nebulizers, enabling, e.g., work with microflows of solutions at high efficiency, new developments in ultrasonic nebulization, in electrothermal evaporation, laser ablation and hydride generation. Innovation in the types of mass spectrometers used is discussed with special reference to the use of reaction and collision cells, sector field mass spectrometry, time-of-flight mass spectrometry and multicollector mass spectrometers. Challenging applications in the field of speciation, especially in environmental samples with the example of the chromium speciation, and in materials analysis, with special reference to the analysis of ceramic powders with and without on-line matrix removal, are also discussed.
    Type of Medium: Electronic Resource
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