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  • Gas chromatography  (61)
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  • 1
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Esterification in aqueous solution ; n-Butyl esters of C2−C16 dicarboxylic acids ; Dicarboxylic acid analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary C2−C16 dicarboxylic acids were esterified in aqueous solution in the presence of sulfuric acid. Esterification in water/n-butanol mixtures with mole ratios between 0.02 and 2.53 can be utilized for the quantitative determination of the dicarboxylic acids by gas chromatography. The presence of water does not interfere at water/n-butanol mole ratios below 0.27. For mole ratios above 0.27 anhydrous sodium sulfate has been used for binding the water. The mole ratio range was 0.25–0.75 for anhydrous sodium sulfate/water, and 0.32–1.3 for sulfuric acid/anhydrous sodium sulfate.
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 663-667 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Gas solubilities ; Enthalpies of solution ; Polar solutions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The gas-liquid chromatographic method has been used to determine the solubilities and partial molar enthalpies of solution of the gases H2S, CO2 and COS in four polar solvents. The results agree well with literature values obtained using conventional techniques, with the one exception of H2S in N-methyl-2-pyrrolidinone. In this case there is some evidence for the occurrence of adsorption at the gas-liquid interface.
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  • 3
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Esterification in aqueous solution ; n-Butyl esters of aromatic polycarboxylic acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The direct esterification and gas chromatographic analysis of aromatic carboxylic acids as n-butyl esters is described. Derivatization is performed in aqueous solution with n-butanol in the presence of sulfuric acid. The butyl esters of benzoic, phthalic, hemimellitic, trimellitic, trimesic and pyromellitic acids permit their gas chromatographic separation from each other and from fatty acids and alipatic dicarboxylic acids. At mole ratios of [H2O]/ [n-BuOH]≤0.04 the water present does not interfere with the esterification reaction. At mole ratios above 0.04 anhydrous sodium sulfate is used for binding the water, at mole ratios of [Na2SO4 anh.]/[H2O]=0.25–0.75.
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 202-204 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Polysiloxane stationary phases ; Heat of adsorption ; Heat of solution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The changes in the heat of solution of polar compounds and xylene isomers in methylsilicone fluid OV-101 deposited on Chromosorb W AW DMCS were studied. It was shown that the heat of solution increases with an increase of the percentage loading of the OV-101 up to 10%. Solution and adsorption thermodynamic characteristics of the studied system are briefly discussed.
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  • 5
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Metal complexes ; Chemically bonded phase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Packings consisting of diphenylphosphine complexes with CoCl2 and CoBr2, chemically bonded to the silica surface, were synthesized and their retention parameters determined. The packings are capable of specifically interacting with electron-donating compounds by forming π-complexes. The interaction is considerably stronger in the case of CoBr2-containing packing than in the case of CoCl2-containing packing.
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 234-238 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Open-tubular columns ; On-column injection ; Stopped-flow operation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A simple, inexpensive, on-column injector of the septum moving-needle kind is described for quantitative analysis using open-tubular columsn. when operated in the stopped-flow mode an improvement incolumn efficiency is observed combined wit a diminished tendency to produce split-top peaks, particularly for late eluting peaks. Using electronic integration a relative error of about 2.7% was observed for peaks spanning a wide range of sample concentrations and volatilities.
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 243-248 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Carrier gas ; Viscosity ; Influence of temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The vicosity-temperature relationship of the three gases (helium, nitrogen and hydrogen) most frequenly used as the carrier gas in gas chromatography is studied. Based on available data, equaitions are derived to describe this relationship. Using these equations viscosity data are tabulated for the chromatographically important temperature range.
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 260-264 
    ISSN: 1612-1112
    Schlagwort(e): Parabens and their dissolution ; Pharmaceutical dosage forms ; Derivatization ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A specific, sensitive and general applicabla gas chromatographic method is described for the determination of parabens in various liquid pharmaceutical preparations: propylparaben and butylparaben in a liquid antacid dosage form (I); methylparaben, ethylparaben and propylparaben in a syrup (II); methylparaben and propylparaben in a solution for injection (III). Each time one of the parabens is used as internal standard. The parabens are extracted with diethylether and derivatized by silylation. Different columns are used for the analysis of the parabens: 3% SE-30 column, a 3% QF-1 column for different selectivity, a 2% OV-1 column for isothermal operation. Special attention is attributed to the standard: the parabens are dissolved in a minimal amount of 0.1 M sodium hydroxide and extracted in the same way as the pharmaceutical dosage form.
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 294-296 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Configuration ; Resolution ; Alcohols
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The study of the resolution of sixteen secondary aliphatic alcohols by gas chromatography on (+)-dodecyl (2R, 3R)-tartrate, trapping the ascending part of the peak from a conventional filled column, has allowed the determination in a single operation of the sign and order of emergence of enantiomers. A correlation between the configuration of these secondary alcohols and their order of emergence has been established.
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 309-312 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Carboxylic acids ; Acetonyl derivatives
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The preparation of the acetonyl esters of nine aliphatic carboxylic acids is described, the general formula of the derivatives being RCOOCH2COCH3 where R=alkyl or H. The derivatives show good chromatographic properties on both packed and capillary columns. The electron impact and chemical ionisation mass spectra of the derivatives are discussed.
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 449-455 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Thermodynamic relationships ; Retention index ; Peak identification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A thermodynamic criterion, ΔQ, is suggested which permits to estimate the difference in the functional group energy of interactions for two different stationary phases. The linear dependence of ΔQ on the homolog number m of any series Rm X can be used as the thermodynamic criterion for the identification of substances by GC analysis.
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 477-488 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Open tubular (capillary) columns ; Sample capacity ; Column comparison ; Film thickness ; Column diameter
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Wall-coated, open-tubular (capillary) columns prepared from different diameter tubing, with different liquid phase film thickness, are compared with each other and with packed and support-coated open-tubular columns. The comparison is based on the variation of the phase ratio and the capacity factor, and includes column efficiency (HETP, theoretical plate number), resolution, retention time, and sample capacity. Problems associated with the evaluation of the sample capacity are outlined. The influence of temperature on column performance is discussed in detail. Finally, the possibilities of short, wide-bore open-tubular columns prepared with a thick liquid-phase film are demonstrated.
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 37-43 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Methylbromide ; Charcoal tubes ; Pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Air sampling of methylbromide using 900 mg HBr-treated activated charcoal tubes, followed by solvent desorption and FID or ECD chromatographic analysis, makes it possible to evaluate concentrations ranging from 0.2 ppm (1 mg×m−3) to 250 ppm (1g×m−3) at ambient temperature even with a high hygrometric level. Thermal desorption does not lead to satisfactory results.
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 60-66 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Mass loadability ; Stationary phase capacity ; Capillary columns
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary In GLC the mass load can be normalized with respect to the amount of stationary phase in one plate. This quantity can be used for a specified solute-liquid phase combination in any capillary or packed column, irrespective of the column dimensions or the number of plates. For each individual solute in a given stationary phase a unique factor β″ can be found, which accounts for the specific shape of the isotherm of this particular combination. this factor β″ corresponds well with the activity coefficients of the solutes in the stationary phase, by which a fairly good approximation of the mass loadability of the column at hand can be made without need for experiment.
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 552-558 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Radio gas chromatography ; 3H- and14C-labelled compounds ; Isotope effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Radio gas chromatography (RGC) is a valuable tool for the analysis of radioactively labelled compounds. Recent advances in capillary GC, especially in column technology and instrumentation have also induced new possibilities in this field. With regard to the preservation of the achieved separation efficiency, radioactivity detection is the main problem in capillary RGC. Based on published data and on our extensive experience in conventional RGC, a simple, reliable and versatile method has been developed for the radioactive detection: purge gas is added to the effluent of the capillary column and the RGC detection unit with conversion tube and flow-through proportional counter is used maintaining small dead volumes and dimensions. The influence of the extra-column volumes and of the total gas flow rate (of the carrier, purge and quenching gases) on the peak shape was investigated. It was also found that the isotopic effect commonly known in GC of2H- and3H-labelled compounds is hardly measurable for larger [G-14C] labelled species such as [G-14C] labelled higher fatty acids with high isotopic abundance of14C, even on the highly efficient capillary columns. The quantitative aspects of the detection method used are discussed and some applications to the analysis of labelled biochemicals (amino and fatty acids) are demonstrated.
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 644-648 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Ion exchange resins ; Polymeric supports ; Chloromethanes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The retention of compounds of various classes on macroporous sulfonated cation exchangers in the form of the fourth period elements in Mendeleev's table (i. e. in the K, Ca, Co, Ni, Cu, Zn-forms) has been investigated. It has been shown that these sorbents are characterized by a high specificity of molecular interaction. It has also been established that the gas-chromatographic properties of cation exchangers depend on the nature and valency of the metal ion in the ionogenic group.
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 109-112 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Packed columns ; Immobilized stationary phase ; Poly(ethylene glycol) phase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Carbowax 20M poly(ethylene glycol) stationary phase was immobilized on Chromosorb W by cross-linking with pluriisocyanate. The properties of the prepared packing material were investigated. Column efficiencies of 10,960 and 7,510 theoretical plates/meter were obtained for n-pentadecane and 1-heptanol, respectively.
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 159-163 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Flame photometric detector ; Sulfur compounds ; Response quenching
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The long time retardation of the main hydrocarbon peak in the chimney of the flame photometric detector greatly reduces the responses of later-eluting sulfur compounds. In the absence of hydrocarbons in the flame, the slope (s) of the log I vs. log [S] plot (where I is the sulfur response and [S] is the sulfur concentration in the sample) is of the highest value and is constant for all experimental conditions tested. Flame hydrocarbons cause the s value to decrease, and this is dependent on the oxygen to hydrogen ratio in the flame (O/H) and, under certain conditions, also on the sulfur to carbon ratio (S/C) of the sample. The abnormalities observed in the determination of methyl thiol in natural gas are explained on the basis of the present study.
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 631-632 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Wide-bore glass capillary columns ; End-sealing ; Static coating
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary An end-sealing method to be used for static coating of wide-bore glass capillaries is described. After the capillary was completely filled with the coating solution, one end is connected to a gas-tight syringe (10-ml volume) via silicone tubing and the other end is fixed with shortcutted silicone tubing for sealing with a plug. The method is highly successful.
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  • 20
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Ethyl carbamate ; Direct injection quantification ; Cold injection system ; Optimised SIM
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary An integrated procedure is described which allows direct injection quantitative screening to single figure parts per billion (μg/L) levels of ethyl carbamate in the natural matrix of distilled alcoholic beverage. Injection and detection performance was studied and optimized to allow this routine, reproducible, trace analysis without any sample pre-treatment. All aspects of the analysis including autosampler run sequences and automated internal standard report generation are initiated and controlled from a single GC/MS workstation.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 455-460 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Surface free energy ; Silane-covered materials ; Film pressure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The surface free energy, or film pressure, π0, is measured for mica (Mica HK), silane-covered mica (Mica NP), Chromosorb W DMCS and glass beads. The film pressure is obtained from gas chromatography. The materials are used as adsorbents and benzyl alcohol and n-dodecane are used as molecular probes. Adsorption isotherms at 353 K are obtained from gas chromatography data and the surface free energy is computed with the help of the Gibbs equation. Values of π0 for a given surface are found to vary with the molecular probe. With benzyl alcohol π0 varies from 44 erg/cm2 for Mica 60 HK to 76 erg/cm2 for glass. In the case of n-dodecane π0 is found to vary in the same manner but the values range from 25 to 45 erg/cm2. The results are in good agreement with the values obtained with the contact angle method.
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 469-471 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Headspace analysis ; Ethylene oxide ; Capillary column
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A headspace gas chromatographic method for determination of traces of ethylene oxide (EO) in sterilized materials has been developed. The method allows the determination of the amount of EO by putting the samples directly into acetonitrile and analysing by means of headspace GC. The procedure described is simple, sensitive, reproducible and linear. The lower limit of detection is 0.015 μg/g of sterilized material.
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 24-26 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Anesthetics ; Pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A sensitive capillary gas chromatographic method is described for the simultaneous determination of lidocaine, tetracaine, procaine and dibucaine. The method was applied to the determination of anesthetics in tissue homogenates incubated at 38°C at doses between 10 and 400 mg/kg. In the liver tissue thein vitro metabolization of the studied anesthetics is most rapid for tetracaine, also fast for procaine, while for lidocaine and dibucaine the metabolization is very slow. In brain tissue thein vitro metabolization of anesthetics is very slow. The method shows good analytical parameters: linearity between 5 and 40 μg/ml; day-to-day reproducibility ca. 8% for a concentration of 20 μg/ml, precision ca. 7% for a concentration of 20μg/ml. Accuracy is also very good.
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 639-642 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Capillary columns ; Split injection ; Sample tailing and cold trap effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Sample plug tailing together with a cold trap effect brings about discrimination against low boiling components at an initial column temperature above the boiling point of the solvent. In conventional split injection, this compensates for the opposite effects of such factors as the gas phase viscocity change and the pressure wave during the split period, and reasonable results are obtained. In stop-flow injection, however, since the influences of the opposite factors are diminished, the sample plug tailing and the cold trap effect may produce results showing lower than true concentrations for the low boiling components.
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 313-314 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Fused-silica columns ; Static coating ; Sealing method
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary In this paper a new sealing method for the static coating of capillary columns is described. When one end of the fully filled capillary was immersed into liquid nitrogen in a Dewar flask, the coating solution at this end would be frozen and became a temporary seal, and an air-free solvent/seal interface was obtained. No bumping has ever been found at the interface, even when butane was used as solvent. By applying this sealing method, several capillary columns, including some narrow bore capillary, had been successfully coated.
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 502-504 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Retention variation ; Effect of sample composition on retention
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The variation of the retention index of a solute due to the presence of a closely neighboring peak is discussed. The neighboring peak is likely to modify the original stationary liquid by forming a temporary “mixed” stationary phase. The extent of the retention index variation is influenced by many experimental parameters and becomes pronounced when the stationary phase is overloaded by the neighboring peak and the film thickness of the stationary phase is not very large. However, the exact extent of this variation is rather unpredictable. The practical significance of this finding is also discussed.
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 367-368 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Open tubular (capillary) columns ; Variation of film thickness ; Thick-film columns ; Mass transfer terms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The factors characterizing the influence of the variation of the liquid phase film thickness on the mass transfer terms in the Golay equations describing the performance of open tubular columns are investigated and numerical values are given.
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  • 28
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; FAME fingerprinting ; Animal fats ; Transesterification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The triglycerides of animal fats from milk, meat or cheese can also be characterized by the gaschromatographic pattern of the fatty acid methylesters (FAME) after conversion by an unsophisticated transesterification procedure. Even from the FAME pattern falsifications of commercial animal fats can be revealed by the fast separation of the FAME using a standard CW 20 M (polyethyleneglycol) capillary column. Characteristic patterns of FAME originating from different animals are shown. The patterns of the FAME from different races of the same animal are very similar, so that the characterisation according to the type of animal is not disturbed.
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 71-76 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Electron-capture detector ; Constant-current mode ECD ; Non-linearity of ECD
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The effects of the ionization source activity, sample input rate, electron capture rate constant, ventilation rate constant and baseline frequency on the linearity, detectability and sensitivity of the constant-current electron-capture detector (CC-ECD) were investigated. The proposed model representing an extension of the Wenthworth-Lovelock model proved to be useful in demonstrating that the CC-ECD can be highly nonlinear for strong electron capturers, at high ionization source activities, at a low ventilation rate constant and at low baseline frequencies. Optimization of the CC-ECD operation is possible by a reasonable adjustment of the studied parameters.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 611-616 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Coke oven gas evolution ; On-line gas analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A gas chromatograph will thermal conductivity detector (TCD) connected on line via a cleaning train to the semi-industrial scale Coke Oven Text Plant of the Spanish National Coal Institute (INCAR), has been used to control the evolution of the permanent gases during the coking process. The undesirable presence of oxygen in the coke oven gas can be detected with this system that will be applied to determine the end of the coking process by quantitative analysis of the gas evolved.
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 182-184 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Micropacked columns ; Alkyl-modified silica ; Hydrocarbons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Micropacked columns for liquid chromatography were evaluated for the gas chromatographic separation of hydrocarbons. A glass-lined stainless-steel tube of 30 cm×0.3 mm i.d., packed with 5-μm alkyl-modified silica, was employed as the separation column. The micropacked columns were successfully applied to the separation of components of a light oil and a kerosine.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 205-208 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Kováts indices ; Numerical interpolation ; Dead time
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Comparison with normal procedures shows that numerical interpolation of the logarithms of gross retention times generates quite useful Kováts indices for gas chromatographic analysis. The dead time concept is not used in the interpolation.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 306-310 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Adsorption studies ; Clinoptilolite ; Zeolite
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Adsorption properties of NH4-clinoptilolite, thermally treated at 400, 550 and 650°C, were investigated by gas-solid chromatography. Adsorption of ten hydrocarbons, including aliphatic, alicyclic, chlorinated and aromatic compounds is discussed in the light of adsorbate-adsorbent interactions. The imporatant thermodynamic parameters of adsorption are determined. A detailed discussion is presented on the alteration of the surface properties of NH4-clinoptilolite caused by thermal treatment. Experimental data obtained show that NH4-clinoptilolite treated at 650°C can be successfully employed as a column packing in analytical gassolid chromatography.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 436-440 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Liquid crystal stationary phases ; PAH ; FAME ; Mesomorphic polysiloxane phases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The gas-chromatographic properties of two mesomorphic polysiloxane (MEPSIL) stationary phases, one smectic (SB) and the other nematic (N), were investigated. The retention indices and separation factors (relative retentions), α, of several pairs of polycyclic aromatic hydrocarbon (PAH) and fatty acid methyl ester (FAME) isomer solutes were used to gauge differences in the selectivity provided by each. The heats of solution of the PAH showed that the smectic MEPSIL is more selective for solutes with different length-to-breadth ratios. Also, five peaks were resolved for sixcis andtrans octadecenoic FAME isomers with this solvent. The nematic MEPSIL, on the other hand, was found to be more useful at higher temperatures because of its higher clearing point. In addition, solute capacity factors were smaller than those observed with the smectic MEPSIL, as evidenced by lower retention indices. The former was therefore more useful for the analysis of high molecular-weight PAH.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 556-560 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Colloidal stationary phases ; Liquid crystals as stationary phases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Colloid systems consisting of the nematic liquid crystals p,p′-azoxyphenetol and p,p′-methoxyethoxyazoxybenzene and high-disperse mineral particles (aerosil, carbon black) are proposed to be used as stationary phases in gas chromatography. The dependence of the retention of normal paraffins, Rohrschneider and McReynolds test solutes (benzene, ethanol, methyl ethyl ketone, nitromethane, pyridine, butanol-1, 2-pentanone, and nitropropane) on the composition of the colloid systems was investigated. The investigated colloid sorbents including liquid crystals retain their selectivity for meta/para isomers up to 50% of the aerosil content and practically at all studied carbon black concentrations.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 617-619 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Chlorinated methanes ; Activated charcoal sampling ; Pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A sampling method using activated charcoal, followed by percolation with ethanol and FID or ECD chromatographic analysis, depending on the concentrations to be monitored, makes it possible to evaluate concentrations of methylene chloride between 5 and 1000mg m−3, chloroform between 0.1 and 2000mg m−3, and carbon tetrachloride between 0.015 and 1000mg m−3.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 139-142 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Silica surface ; Silanols ; Strongly interacting sites
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The paper describes how the method of gas-phase titration of the strongest adsorption sites can be utilized to calculate a relative strength of interaction of the sites with chromatographic solutes. An excellent correlation with earlier, theoretical predictions of Giddings is noted. Significant influence of the sites on the width of a chromatographic band is observed when the interactions are an order of magnitude stronger than those of normal sites.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 167-169 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Determination of monomer in polymers ; Sealed glass capillary sampling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Residual styrene in polystyrene and free phenol in phenolic plywood adhesive have been determined by sealing samples in glass capillary tubes. To prevent loss of sample the ends of the capillary tubes were sealed with a kind of putty made of anhydrous calcium sulfare, calcium carbonate and a small quantity of phenylmethylsilicone fluid. No volatile compounds were released from this sealing material when the capillary tubes were placed in a quartz vaporising furnace at temperatures up to 300°C.
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  • 39
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; GC/MS and headspace GC ; Elastomeric stoppers for injectables ; Trace hydrocarbons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Elastomeric stoppers for injectables have been surveyed by means of GC/MS screening. Residual contamination by hexanes (2-methylpentane, 3-methylpentane, n-hexane, methylcyclopentane, cyclohexane) toluene and xylenes occurred in all the samples tested. A headspace GC purity test is suggested, by using these residual chemicals as purity indexes.
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  • 40
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Optimization of gas-solid separations ; Plate height equation ; Computer mapping procedure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary This paper proposes an optimization model for gas-solid chromatographic separations in a non-linear programming form and an approximate equation of the plate height for the model. A computer-modified mapping procedure is also described for searching the optimum separation conditions. Just five experiments and about 20 minutes of the computer time are needed to establish the optima of column temperature and of the carrier gas linear velocity. The relative deviation between the predicted and the experimental values was found to be within 20% for the plate heights, and within 1.5% for the retention times.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 241-248 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Renewal theory ; Monte-Carlo simulation ; Prediction of retention and peak widths
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new method for prediction of gas chromatographic retention times and peak half widths is based on the renewal theory. The only requirements are the heats of vaporization of the compounds to be separated and one calibration measurement. With this data, retention times and peak half widths can be predicted for isothermal as well as temperature-programmed gas chromatography. For the separation of non-polar substances on non-polar stationary phases the prediction error for retention times is approx. 1–2%. First simulations of polar molecules and polar stationary phases indicate that this method is also applicable in these cases but some extension will be required.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 11-14 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Cross-linked Stationary phase ; Immobilized Stationary phase ; Packed columns ; Trapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A coating of silicone SE-54 on Chromosorb W has been converted to an analytically stable, immobilized stationary phase layer by cross-linking with an organic peroxide. Up to 10% by weight has been applied in this manner. Excellent high temperature qualities are exhibited, such as low bleeding and good base line stability, during typical analyses. Poly (2,6-dimethyl-p-phenylene oxide) has also been crosslinked as a surface coating on Chromosorb W with an organic peroxide. From 3 to 4% by weight has been immobilized in this way. The resultant packing material, following high temperature conditioning, has been examined for use as an adsorbent of trace substances, similar to the applications to which such adsorbents as Tenax GC have commonly been applied, e.g. trace analysis of air. It appears to exhibit satisfactory properties for this analytical purpose.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 21-22 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Isopropylidene-glucose ; Glucose ; GC of TMS-derivatives
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary This paper describes the gas chromatographic separation of the mixture of di- and mono-O-isopropylidene-D-glucose and D-glucose as their trimethylsilyl derivatives. The use of OV-101 as liquid phase provides a complete separation for the all components in the mixture. Quantative analysis was performed using xylitol as the internal standard for di- and mono-O-isopropylidene-D-glucose, and sorbitol as the internal standard for α-and β-glucose.
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  • 44
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Nuclear magnetic resonance ; Terpenes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A procedure is described for recording1H NMR spectra of flowing gaseous GC fractions boiling as high as 200°C. The line width of the signals in the NMR spectra is smaller than 2.2Hz.
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 556-559 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Liquid chromatography ; Tetramethrin ; Residues
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A method is described for the analysis of tetramethrin aqueous formulation and residues of tetramethrin on woolen cloth. The samples were extracted with acetonitrile and partitioned with benzene. Interferences were removed by liquid column chromatography with acid alumina and eluted with 10% ethyl acetate-hexane. Analysis was by gas chromatography with a 10% UCW98 (methylsilicone) column. Detection was made with the flame ionization detector to avoid the repeated dilutions necessary with use of the electron capture detector.
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 615-618 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Retention index ; Electric parameters ; Physico-chemical relationships ; Structure-retention study
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new equation is derived relating the retention index to the molecular polarizabilities, ionization potentials and permanent dipole moments of the stationary phase and the solute. Various implications of this equation to quantitative structure-retention relationships are discussed.
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  • 47
    ISSN: 1612-1112
    Schlagwort(e): Aldehydes and ketones ; 2,4-dinitrophenylhydrazine-coated silica gel ; Gas chromatography ; Column liquid chromatography ; Pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary After a brief review of several methods described in the literature this paper discusses air-sampling on 2,4-dinitrophenylhydrazine-coated silica gel and identification requirements for aldehydes and ketones most commonly found in industrial pollution. Quantitative analysis of formaldehyde and acetaldehyde either by GC or by HPLC techniques is established using a dynamic system producing test atmospheres and compared with the usual colorimetric determinations.
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  • 48
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Microwave plasma detector ; Thiophenes ; Shale oil distillates
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A series of alkylthiophenes and dimethyl disulfide were tentatively identified in an oil shale retort gas condensate from a 6-kg bench-scale retort using gas chromatography with a microwave-induced helium plasma detector (GC-MIP). The sulfur species were present in concentrations ranging from 1.5 to 10.7 mol ppm in the undiluted offgas. The GC-MIP technique was successful in selectively detecting the sulfur components in the complex mixture. Quantitation was simplified relative to GC with flame-photometric detection because of the absence of quenching or other interference problems at the concentrations studied. Attempts to determine stoichiometry of the sulfur components by comparison of carbon, hydrogen, and sulfur ratios with those of standards were unsuccessful because of the complexity of the carbon and hydrogen chromatograms.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 55-59 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Air pollutants ; Adsorbent enrichment ; Thermal desorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new automatic method is described for quantitative determination of some light C2–C4 hydrocarbons in urban air: ethene, ethyne, propane, propene, butane and iso-butane. This method is based on an enrichment step at room temperature using a solid sorbent and subsequent thermal desorption for gas chromatographic separation and FID detection. The instrument is built up of a small commercial gas chromatograph and a laboratory-made trap and desorption unit. The sampling parameters, sample volume, concentration and humidity of air have been investigated.
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 596-600 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Mass spectrometry ; Azines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary We have studied the gas chromatographic behaviour of several 3-methyl-2-benzothiazolone-azines. In HPLC analysis all the unsymmetrical azines show double peaks, whereas in HRGC analysis only some of these compounds show the two peaks corresponding to the Z (syn) and E (anti) isomers. By means GC/MS analysis the mass spectrum of each azine was recorded. We have assigned the E and Z configurations to the first and second gas chromtographic peaks on the basis of the ratio between the relative abundances of the two most significant framment ions at m/z 163 and 164.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 221-224 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Large volume sample injection ; Closed on-column injector
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new simplified version of a “closed” on-column injector is introduced. Because of its design isobaric injection conditions do not have to be followed and a wide range of injection temperatures above the boiling point of the sample solvent can be chosen for on-column injections in capillary gas chromatography. Also, when following certain basic injection rules, injections of large sample volumes (≥20 μl or more) give accurate and reproducible results without further problems.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 233-237 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; FTIR ; Hemoglobin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The use of N, O (S)-tert.-Butyldimethylsilyl derivatives of amino acids for capillary gas chromatography and FTIR identification of amino acids is described. Rapid identification is achieved by computerised comparison of FTIR spectra. Derivatives that are characterised by identical sets of ions in gas chromatography-mass spectrometry experiments are clearly distinguished and identified by means of their infrared spectra. This, for example, is the case with alanine, β-alanine and sarcosine, which norvaline and valine, and with norleucine, leucine and isoleucine. Unknows are also promptly detected. This is especially useful in screening biological samples for less common amino acids. Screening of hemoglogin hydrolysates for amino acid adducts is exemplified.
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 483-488 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Trichloroethyl ester ; Dicarboxylic acid ; Urine samples ; Electron capture ; Biological monitoring
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Dicarboxylic acids were esterified by 2,2,2-trichloroethanol by using trifluoroacetic anhydride and phosphoric acid as catalysts. The method was developed to facilitate the evaluation of workers' exposure to sensitising acid anhydrides and other compounds metabolised to acids in the body. The sensitivity of the acid determination in urine was in the order of 2–4 ng ml−1 for aliphatic and alicyclic acids and 15ng ml−1 for phthalic acid.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 499-508 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Electron capture detector ; Space-charge model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Mathematical analysis, allowing the determination of the distribution of the electron and positive ion concentration in an electron-capture detector with a cylindrical electrode arrangement and with constant and pulsed voltage supplies, has been carried out. The measurements obtained confirm the assumptions concerning the “space change” model of the ECD introduced by Gobby et al. and cast doubt upon the general assumption of the complete removal of the electrons from the detector by the voltage pulse. The physical factors influencing the current characteristics of the detector and the possible distortions connected with the electrode geometry have been explained on the basis of the measurements carried out.
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 333-339 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Catalytic reactions ; Adsorption and desorption rate constants ; Reversed-flow techniques
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A small volume of reactant, 1-butene, is injected onto a catalytic bed and is allowed to diffuse away from it together with the product butane, along a narrow empty chromatographic tube; the latter is connected perpendicularly to the middle point of another similar tube through which hydrogen flows as reactant and carrier gas, transferring both 1-butene and butane to the detector through an analytical column. By using the reversed-flow GC technique, extra peaks are obtained in the chromatographic trace, sampling the concentration of both the readtant and product at the junction of the two tubes as a function of time. These concentrations are the result of the diffusion of the substances along the narrow empty tube, modified by the adsorption-desorption rates and the rate of the catalytic reaction. From the extra peaks of the reactant and product, a number of physicochemical quantities pertaining to the catalytic reaction can be calculated simultaneously, using appropriate mathematical analysis. These include adsorption rate constants, reaction rate constants, desorption rate constants, partition coefficients, and the overall mass transfer coefficients of the reactant across the gas-solid boundary of the catalytic bed.
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  • 56
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; KF·2H2O as stationary phase ; Alcohols ; Organic bases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Potassium fluoride crystal dihydrate is used as the stationary phase for the rapid analysis of polar compounds in aqueous solutions. KF·2H2O is compared with some conventional stationary phases, organic salts and molten crystal hydrates of inorganic salts.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 237-240 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Slope of log plot ; Homologous series ; Retention index ; Retention time ; Uncertainty ; Free energy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The free energy of partition of a methylene group $$\Delta G_{CH_2 }^ \circ $$ is constant within a homologous series down to C5 and nearly constant to C3, contrary to the finding of Golovnya and Grigoryeva [5]. Retention indices are linear with carbon number: values may be extrapolated from higher carbon numbers to C5 within experimental uncertainty, to C4 with error no greater than 5 units and to C3 with error no greater than 10 units. Error in extrapolating the logarithm of the adjusted retention time, log t′R, to C5 is thus negligible, to C4 has possible error up to 5b/100 and to C3 up to 10b/100, whereb is the slope of the plot of log t′R against carbon number.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 631-638 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Headspace GC/FTIR ; Optimization ; Detection limits ; Cryogenic trapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary For the trace analysis of volatile components in a nonvolatile matrix, the headspace sampling technique offers the potential to lower detection limits in GC/FTIR experiments. Optimization of chromatographic operating parameters for Headspace GC/FTIR is discussed, aiming at the best compromise between maximum chromatographic resolution and highest S/N ratio of the infrared spectra. It is shown that the combination of headspace sampling with cryogenic capillary head trapping is able to provide Headspace GC/FTIR with the best performance in terms of sensitivity and chromatographic resolution.
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  • 59
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Reaction rate studies ; Dicyclopentadiene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The gas chromatographic reactor technique was used to study the kinetics of dicyclopentadiene dissociation in several liquid phases (Versamid 900, neopentyl glycol sebacate, Triton X-305, Carbowax 6000, ethylene glycol phthalate and diethylene glycol succinate). Reaction rates and Arrhenius parameters are reported in the temperature range of 170–200°C. Kinetic data for the lower polarity liquid phases are in good agreement with literature values for liquid phases of the same nature reported previously. Reaction rates are higher when polar liquid phases are used. This behavior can be explained as a result of side reactions which lead to high molecular weight compounds which can be observed in the reaction chromatogram.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 385-390 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Capillary column ; Split injection ; Stop-flow method
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Major concerns in the development of the stop-flow split injection are discussed. Split ratio fluctuation caused by the pressure wave, solvent recondensation and gas viscosity change can be substantially diminished through the formation of a nearly uniform gaseous sample plug. Instrumental variables exerting influence on the accuracy of quantitation were studied. Higher injector temperature and the use of a carrier gas with higher heat conductivity benefit the quick vaporization of the sample liquid, and thus, help in the formation of a sample plug with more unformity.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 405-411 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Gas chromatography ; Concentration of volatile flavor compounds ; ODS packing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Volatile flavor compounds in aqueous model systems, distillates of coffee extract and juices such as apple, tomato, pineapple and grape were adsorbed on an ODS column during HPLC and monitoring absorption at 280nm. The adsorbed volatile compounds were eluted with a small volume of ethanol. Volatile compounds in the eluates were concentrated 22 to 100 times those in the distillates. Recovery of compounds was 50–90%. Breakthrough of specific compounds such as γ-valerolactone, furfuryl acetate and t-2-hexenal in the model systems and several compounds in the juice distillates was detected by capillary GC. Pattern similarity calculated between the GC profiles of a juice distillate and the corresponding eluate gave a qualitative comparison. This novel and versatile method utilizing conventional RP-HPLC may be widely applicable for concentrating volatiles in aqueous systems, at levels from ppm to ppb.
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