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  • Gas chromatography
  • Springer  (164)
  • American Chemical Society (ACS)
  • National Academy of Sciences
  • 1990-1994  (164)
Collection
Publisher
  • Springer  (164)
  • American Chemical Society (ACS)
  • National Academy of Sciences
  • Wiley-Blackwell  (53)
Years
Year
  • 1
    ISSN: 1434-4475
    Keywords: Gas chromatography ; Polyphenyl ethers ; Lubricants, synthetic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The described synthesis of synthetic lubricants based on polyphenyl ethers requires an analytical characterization of the isomerization step, which is important to the process optimization. The separation of the intermediates succeeds with gas chromatography; the isomers are determined using a retention index system. The obtained results are compared with the composition of the final product, which was investigated by HPLC analysis.
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  • 2
    ISSN: 1432-2285
    Keywords: Abies alba ; Abscisic acid ; Damage ; Gas chromatography ; Needles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The amount of abscisic acid (ABA) in needles of silver fir from a natural location was investigated with regard to position in the crown, damage, seasonal variation, and needle age. Because of problems of quantification of ABA in coniferous needles, which contain numerous secondary plant products, a method for reliable determination of both isomers cis-trans-ABA (c-ABA) and transtrans-ABA (t-ABA) was developed. By means of gas chromatography (GC) using an electron capture detector (BCD) and a programmed temperature vaporizer (PTV) injector complete separation of both compounds was achieved. Two different pairs of fir were investigated — in each case a damaged and a healthy tree. Needles from both trees from the first and the second pair collected in September contained 500–1100 ng c-ABA/g fresh weight (FW), and the concentrations of t-ABA varied from 400 to 700 ng/g FW. Investigations from the second pair show highest amounts of 2900 ng/g Fw c-ABA and 1800 ng/g FW of t-ABA in May and June. For the first pair a higher c-ABA content was found in needles from the top of the crown than in those from the middle and the base. This difference could not be confirmed in the analysis of the second pair. Because of the strong natural deviation no statistically significant difference between the healthy and the damaged tree was found. The first pair of firs examined showed a higher t-ABA concentration than the second one. In this case the highest amount was found in the top of the crown. Methodical mistakes during the clean-up procedure and in quantification by gas chromatography could be excluded. The presence of c- and t-ABA in the purified extract was corroborated by mass spectrometry. With regard to the seasonal variation both isomers of ABA show an unequivocal trend. The maximum concentration is achieved in May to June, whereas the content is minimal in August/September. In any case the level of t-ABA is lower than that of c-ABA. No correlation between the amount of ABA and the needle age could be established.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 35 (1993), S. 649-652 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Triglycerides in cheese ; Programme temperature (PTV) injection ; Silica capillary columns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A rapid gas chromatographic method for the analysis of triglycerides in cheese on a capillary column with a programmed temperature vaporizer has been developed. Fat were extracted with hexane to dryness. The reproducibility of the method was assessed and the coefficient of variation for the total triglycerides was 2.50%. Recovery of individual triglycerides ranged between 87 to 105%.
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  • 4
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Curie-point pyrolysis ; Multivariate analysis ; Sodium dodecylbenzene sulfonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Multivariate analysis can be applied to quantitative analysis of sodium dodecylbenzene sulfonate (DBS) by pyrolysis gas chromatography. The pyrograms obtained from mixtures of DBS and polyoxyethylene lauryl ether (PEG) were normalized for the peak heights and areas of several internal standards which appeared in every pyrogram, against the characteristics peaks for DBS and PEG. This normalization method gave smaller experimental errors than when using one internal standard. The normalization values were used for cluster analysis unchanged. The values were calculated correlation coefficients and principal component analysis was performed using 11 data base and a set of sample data simultaneously. One calibration curve was calculated from the principal component scores. The DBS content of a sample was obtained from the calibration curve. Calculated values were in fair agreement with theoretical values.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 36 (1993), S. 187-190 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Solid-phase extraction disks ; Pesticides ; Soil analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A systematic study comparing the methodology and analytical results obtained in an investigation of seven pesticide residues (Molinate, Atrazine, Carbofuran, Pirimicarb, Prometryn, Malathion and Tetrachlorvinphos) in soil samples is reported. Solid-phase extraction (SPE) using glass columns and 47 mm disks of octyl and octadecyl-bonded silica was used in the pesticide analysis. The best extraction efficiency and clearest extracts are obtained with C8 disks. The analyses were carried out by capillary gas chromatography with nitrogen and phosphorus detection. Recovery experiments were performed at ppb levels in spiked soil samples. The average recoveries of the compounds were 53–77%. Detection limits are between 5 and 30 ng g−1 based on 5 g moist soil sample. The method was validated by comparing it with conventional liquid-liquid extraction.
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  • 6
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Activity coefficients ; 18-Crown-6-ether and tetraethyleneglycol dimethyl ether ; Thermodynamic properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The thermodynamic properties of different solutes at infinite dilution have been determined at 323.15 K. Deviations from ideality are discussed in terms of different contributions. The activity coefficients are compared with the calculated values by the one group contribution method.
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  • 7
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Fatty acid methyl esters ; Diesel fuel substitute ; Glycerol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A GC method for the determination of free glycerol in vegetable oil methyl esters used as diesel fuel is described. The sample preparation includes dissolving in dimethylformamide, silylation with bistrimethylsilyltrifluoroacetamide (BSTFA) and separation on a methyl silicone capillary column using either FID or MS detection. The recovery was tested using standard samples containing known amounts of glycerol. The results of the analysis of different samples were compared with those obtained by enzymatic determination. The method described offers a far more sensitive and quick determination of free glycerol compared to other methods.
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  • 8
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Electron capture detection ; Trichothecenes ; Cereal grain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Various analytical methods developed for trichothecene determination, including TLC, HPLC, GC, supercritical fluid chromatography (SFC) and enzyme immuno assay (EIA) are reviewed. In addition a new method is described for the simultaneous determination of the trichothecene mycotoxins deoxynivalenol (DON), nivalenol (NIV), 3-acetyldeoxynivalenol (3-ADON), diacetoxyscirpenol (DAS), T-2 toxin (T-2), HT-2 toxin (HT-2) and T-2 triol (TRIOL), in Austrian wheat and corn samples by GC-ECD. A clean-up procedure has been developed using a combination of liquid-liquid and liquid-solid extraction. Trichothecenes were detected as their heptafluorobuturyl esters or alternatively as trimethylsilyl ethers (only sensitive for deoxynivalenol and nivalenol) using nandrolone or chloramphenicol as internal standard. Four derivatization techniques using HFBI, HFBA+DMAP on polystyrene, TMSI and TMSI+BSA+TMCS have been studied and the advantages and disadvantages of each are discussed. Quantification of trichothecenes from 10 to 1000 ppb in cereals could be accomplished routinely.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 37 (1993), S. 215-217 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Unified retention indices ; Dimethylsiloxane stationary phases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Gas chromatographic, unified retention-indices of 56 alkylbenzenes up to C15 on dimethylsiloxane OV-101 and SE-30 stationary phases are given. These values agree well with the corresponding experimental values used in the statistical treatment of the experimental data.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 37 (1993), S. 259-263 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Quantitative analysis ; Ethylene oligomer by-products ; n-Alkanes, n-alkenes and 2-alkyl-1-alkenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A gas chromatographic method using temperature-programmed poly-dimethylsiloxane OV-101 and poly(pheny ether) (5 rings) capillary columns was developed to separate and quantify the reaction by-products in ethylene oligomers. It was found that the content of 2-alkyl-1-alkenes, 2-alkenes and n-alkanes in the C8−C18 α-olefin fractions amounts to 29, 10 and 2.6% respectively.
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