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  • 1
    Electronic Resource
    Electronic Resource
    Correlation of iron content, spectral forms of chlorophyll and chlorophyll-proteins in iron deficient cucumber (Cucumis sativus) (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 93 (1995), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Leaves and chloroplast suspensions of severely and slightly iron deficient cucumber (Cucumis sativus L.) plants were characterized by low-temperature fluorescence emission spectroscopy and Deriphat polyacrylamide gel electrophoresis. The emission spectra of the chloroplast suspensions were resolved into Gaussian components and those changes induced by iron deficiency were related to the variations in the chlorophyll-protein pattern. The symptoms described with these methods were also correlated with the iron content of the leaves. It was concluded that the lack of physiologically active iron caused a relative decrease of photosystem I (PSI) and light harvesting complex I (LHCI), together with the long wavelength fluorescence, especially the 740 nm Gaussian component, and. to a much lesser extent, of the photosystem II (PSII) core complexes (relative increase of 685, 695 nm components). However, the relative decrease in the amount of light harvesting complex II (LHCII) was followed by a relative increase in its fluorescence band at 680 nm, showing that energy transfer from LHCII to core complex II (CCII) was partly disturbed. Thus iron deficiency affected the photosynthetic apparatus in a complex way: it decreased the synthesis of chlorophylls (Chls) and influenced the expression and assembly of Chl-binding proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1995.tb05127.x
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  • 2
    Electronic Resource
    Electronic Resource
    ICP-AES detection of silicon carbide impurities volatilized in a graphite furnace with the use of carbon tetrachloride vapour (1992)
    Springer
    Microchimica acta 107 (1992), S. 345-358 
    Details
    ISSN: 1436-5073
    Keywords: solid sampling ; electrothermal vaporization ; halogenation ; ICPAES ; silicon carbide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The analytical capability of high-temperature halogenation with carbon tetrachloride vapour in a graphite furnace was investigated for silicon carbide powder with known chemical composition and particle size. Intensity vs heating time curves were determined for analytical lines of Al, B, Ba, Ca, Cr, Cu, Fe, Mg, Mn, Ti, V and Si constituents, volatilized with and without the presence of CCl4 vapour in the furnace atmosphere. Igniting 10 mg SiC at 2100 °C for 60 s in chlorinating atmosphere, the evaporated fraction of most of the constituents was higher than 90% (for Al about 50%). The line intensity vs sample mass (4–26 mg) relationships were linear for all impurities studied, while the intensity of silicon line showed a relatively small change with the sample mass. BEC (background equivalent concentration) values for this solid sampling technique (10 mg loaded sample) were 2–20 fold lower than those calculated for the conventional solution sample introduction method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01244490
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Carbon determination in Si3N4 by slurry atomization ICP-AES (1989)
    Springer
    Microchimica acta 99 (1989), S. 381-387 
    Details
    ISSN: 1436-5073
    Keywords: slurry atomization ; ICP-AES ; silicon nitride ; ceramic materials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Carbon content in silicon nitride powders having mean particle size below 5 μm was determined by slurry atomization inductively coupled plasmaatomic emission spectrometry (ICP-AES). A complete atomization of the solid particles was observed in a low power argon-ICP. The blank value of the carbon signal was reduced by using high purity argon, fresh bidistilled water and an extended torch. Silicon nitride slurries were analyzed by calibration and addition methods with acetic acid as reference. The results were in good agreement with data obtained by a LECO carbon analyzer. A blank restricted detection limit of 0.018% was calculated. The relative standard deviation of the analysis was below 7%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01244694
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  • 4
    Electronic Resource
    Electronic Resource
    Microwave assisted dissolution of aluminium oxide samples (1993)
    Springer
    Microchimica acta 111 (1993), S. 45-54 
    Details
    ISSN: 1436-5073
    Keywords: aluminium oxide ; microwave assisted acid digestion ; inductively coupled plasma atomic emission spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The dependence on time of the efficiency of microwave assisted digestion of Al2O3 samples with various physico-chemical properties in H2SO4 solution (1 + 1) at a temperature of 170 °C and a pressure of 207 kPa has been investigated. Therefore, the concentrations of Al and that of the impurities in the solutions obtained, as well as the masses of residues after different times have been measured. The efficiency of the dissolution was shown to depend on the specific surface area and on the phase-state of the Al2O3. The time demand for total dissolution of the samples ranged from 0.1 to 7 hours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01240166
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  • 5
    Electronic Resource
    Electronic Resource
    Analysis of silicon carbide powder by ETV-ICP-AES (1993)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 346 (1993), S. 1042-1046 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A direct “tandem” atomic spectroscopic method for the determination of Ca, Fe and Ti impurities in SiC powders with various grain size (0.78〈d50〈48.5 μm) has been developed. The method is based on high temperature halogenation of the sample with Freon 12 in a graphite furnace and ICP-AES detection of the evolved sample components. The concentration of the matrix element silicon in the ICP increased to a maximum value after 10s of heating, independent of the grain size of the powder samples. For performing a calibration with standard solutions a finegrained, purified SiC-powder was evaporated simultaneously with the solution residues. The calibration curves produced using this analyte-addition technique and using within-laboratory solid standards were identical within experimental error.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323713
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