ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Gas chromatography  (73)
  • Springer  (73)
  • 2015-2019
  • 1985-1989  (73)
  • 1988  (39)
  • 1986  (34)
Collection
Publisher
Years
  • 2015-2019
  • 1985-1989  (73)
Year
  • 1
    ISSN: 1432-1432
    Keywords: Primordial terrestrial atmospheres ; CH4, C2H2, CO2 ; Prebiotic synthesis ; High-frequency discharge ; Hydrocarbons ; Gas chromatography ; Mass Spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Various hydrocarbons were synthesized by high-frequency discharge in a primordial terrestrial model atmosphere. The products were extracted by benzene or methanol and analyzed by GC-MS. The mean carbon chain length of the hydrocarbons formed by the discharge through pure CH4 gas was less than 6. Benzene was also obtained. Some isomers were obtained for each of the hydrocarbons containing a given number of carbons. When a small amount of C2H2 was added to the CH4, longer chain compounds were formed, as compared with discharge in CH4 only. However, when the amount of C2H2 was increased, unextractable high molecular weight compounds were produced. The amounts of products decreased as the mixing ratio of CO2 to CH4 increased. No hydrocarbons were detected when the ratio of CO2/CH4 exceeded 1.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Flame ionisation detection ; Cyanogen ; Cyanogen chloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The response of a flame ionisation detector (FID) to cyanogen ((CN)2) and cyanogen chloride (CNCI) has been studied. The lower limits of detection for (CN)2 and CNCl were 6×10−12 moles and 2×10−11 moles respectively. In a comparative study a thermal conductivity detector gave as its lower limit of detection for both (CN)2 and CNCl 4×10−11 moles. Both detectors showed excellent linearity over the range 0 to 10 micromoles. The ratio of the gradients of the FID calibrations (CN)2/CNCI were found to be approximately two suggesting the response depended on the cyanide group. The response and stability of the FID was investigated as a function of air and hydrogen flow-rates. The response increased with increasing air flow-rate for both (CN)2 and CNCI up to 300cm3min−1, thereafter no significant increase was observed. On raising the hydrogen flow from 10 to 25cm3min−1 only a slight increase in the sensitivity of the FID towards both (CN)2 and CNCI was observed. At higher flow rates the response for (CN)2 increased markedly whereas at the same flow rates the response for CNCI increased only slightly.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 21 (1986), S. 214-218 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Behaviour of metal acetylacetonates ; Adsorption isotherms ; Heat of solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Specific retention volumes, adsorption isotherms, molar heats of solution and changes of the entropy were determined from chromatographic data, which was obtained by the gas chromatographic separation of metal acetylacetonates. The retention data for Cr(III), Co(III) and Al(III) acetylacetonates were measured at different temperatures and different flow rates. From the retention data other values associated with adsorption and solution phenomena were calculated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Capillary columns ; Immobilized stationary phase ; Carbowax-type stationary phase ; Cross-linked polyurethane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The preparation of an immobilized stationary phase based on Carbowax 20M is described. The stationary phase cross-linking was carried out with Desmodur N 75 or Desmodur L 75, pluriisocyanates. The properties of the prepared stationary phases are compared.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Volatile nitrosamines ; Fused silica capillary columns ; Linear indices
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Fused silica capillary columns of different diameters and polarities are linked to a thermal energy analyzer and a flame ionisation detector for comparison. Extra column effects are discussed. Unsymmetrical homologue nitrosamines are applied in order to assign the volatile nitrosamines most often to be determined by their linear indices rather than by their overall retention times.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Thermionic detector ; Flame-forming agents ; CO2 and water gas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of carbon monoxide were suggested as the flame-forming agent in the thermionic detector (TID). The main characteristics of this detector were studied. It was shown that the optimum flow rate of carbon monoxide is 40 ml/min at an air flow rate of 400–550 ml/min. The response increases twice with the positive potential on the collector. Molar responses of TID were compared with those obtained when using carbon monoxide and hydrogen. For instance, for phosphorus containing compounds they are approximately the same (∼102), while for nitrogen containing compounds in the case of carbon monoxide, there is a 2–5 fold increase in the response. The linear dynamic range for methaphose and azobenzene is 103.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Metal complexes ; Chemically bonded phase ; Specific interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Packings consisting of chemically bonded diphenylphosphine complexes with CuCl2 and CuBr2 were synthesized and their retention parameters determined. The packings investigated are capable of specific interactions with electron-donating compounds and are characterized by particularly high selectivity in relation to cis and trans isomers allowing their complete separation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Micropacked columns ; Quantitation ; Fermentation products
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new method is proposed for the analysis by gas chromatography of volatile compounds found in alcoholic and acetic fermentation samples. The method represents a suitable choice for the accurate and precise determination of 19 compounds (including Methanol) by direct injection onto a single column. Chromatograms of synthetic mixtures as well as actual samples show the capabilities of the micropacked column used.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Simultaneous distillation-extraction ; Cheese volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simultaneous distillation-extraction apparatus proposed by Godefroot has been used for the GC study of volatile components of cheese. 5–10 g of cheese provide a fraction that can be directly injected into a GC or a GC/MS. Two capillary columns (SE-30 and SP-1000) were evaluated, the second one being adequate for quantitative determinations. Camphor was used as internal standard. The coefficients of variation ranged from 1.4 to 11.8. The technique can be used as a fast method for the characterization of cheeses from their volatile component concentrations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 1087-1088 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Log plot ; Homologous series
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The slope of the log plot of the adjusted retention time of a homologous series usually varies from that of the n-alkane series by no more than 2%, though with unusual interactions between the functional group and the stationary phase the difference may be as high as 7%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Preparative scale separations ; Plate model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Two close-boiling materials, diethyl ether (DEE) and dichloromethane (DCM), were separated to investigate the effects of the pure components and the mixture on elution in preparative gas-liquid chromatography. Nitrogen was used as the carrier gas, and the chromatographic column (1 cm I.D. and 0.75m length) was packed with Chromosorb A with different quantities of dinonyl phthalate stationary phase and particle sizes. Below ca. 7% (by wt.) of feed concentration, the experimental elution curves of pure DEE and DCM were almost the same as those of the mixture, and the theoretical plate model can be used successfully to predict the elution curves.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 404-408 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Silica surface modification ; Hexamethylcyclotrisilazane ; Hexamethyldisilazane ; Support materials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The paper is concerned with the structure of an organic layer bonded to the silica surface modified with silazanes. The changes of the retention volumes of hydrocarbons is studied for the silicas modified with hexamethylcyclotrisilazane, hexamethyldisilazane and their mixtures. It is shown that most of the carbon in the layer after hexamethylcyclotrisilazane modification is bonded to the surface by Si−O−Si bonds. This fact supports the assumption of a fragmentation of the cyclosilane used for modification.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Statistical criteria ; Non-linear models ; Constants for n-alkane retention curve ; Multiparametric least-squares adjustment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Multiparametric, least-squares, regression treatment of G.C. data is extended to describe deviations from the usual linear model. Through statistical evaluation of results, four parameters models are generally found adequate and the use of higher degree empirical models is discouraged.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 539-542 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Temperature programming ; Retention index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is presented for the calculation of retention indices at an assigned temperature from temperature-programmed data. If the retention times at two different program rates for the solutes and the n-alkanes are known, the retention indices at an assigned temperature can be calculated directly.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 22 (1986), S. 183-186 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; C2−C5 hydrocarbons ; Pre-Concentration on silica gel ; Sorption efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A short stainless steel column packed with silica gel is cooled to −78°C and atmospheric hydrocarbons are preconcentrated from 3 I of air on it. Desorption to the analytical column is by heating for 10 min to 200°C. Analysis is by GC on OPN-Poracil C at 27°C. The sorption efficiencies were nearly 100% for most of the light hydrocarbons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 125-132 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Non-equilibrium frontal chromatography ; Nonlinear isotherms ; Variable velocity ; Multicomponent mixtures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The paper presents a classification of various theoretical models for multicomponent gas chromatography at u=var for high concentrations of the mixture components with consideration of the major distinctive features of the interphase mass exchange inside the porous grains of the adsorbent and outside them within the porous medium of the chromatographic column. It has been shown that the conditions determining a given front behaviour of multicomponent gas mixture at u=var depend on: theoretical models for the kinetics and dynamics of adsorption; the values of mass exchange parameters inside the porous grains and in the porous medium. Formulae have been derived for calculating the values of the quantities characterising the frontal behaviour in the stage of adsorption and desorption of multicomponent mixture at u=var.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 21-24 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Sample concentration ; Chromatographic evaporation ; Solvent effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Several micro-techniques for the removal of solvent from dilute solutions of volatile compounds have been compared. Large solute losses were experienced when the conventional blow-down technique was applied. Better yields could be obtained with static evaporation procedures, as long as an effective reflux was maintained. However, careful optimization of the vessel design and operating conditions is necessary. The most efficient volume reduction technique was shown to be chromatographic evaporation. Quantitative recoveries were obtained for the compounds tested and the process was significantly faster than static concentration. Moreover, operating conditions (gas flow, temperature) are less critical. With modifications, the principle can be used for the concentration of large sample volumes down to a few microliters.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Stationary phase polarity ; Polarity parameters ; Structure-retention relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The new stationary phase polarity parameters BN and BS evaluated from the concept of the electric intermolecular interactions are used to describe the polarity of polyoxyethylene glycol dialkyl ethers and their sulphur analogs. Relations between the discussed parameters and accepted measures of surfactants' polarity are presented and discussed. The considered parameters are correlated with the compound structures. Structural increments for characteristic fragments of the molecule are calculated and use to predict BN and BS values.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 134-138 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Sulfur ; n-Octane adsorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary From the adsorption isotherms of n-octane on the surface of sulfur at 29.8°C and 40.6°C some thermodynamic functions were determined. On the basis of these data the structure of the adsorbed layer of n-octane is postulated. The molecular interactions and adsorption mechanism are also discussed. It is stated that both quasi-liquid and quasi-sold layers may be formed on the surface of sulfur depending on the surface coverage with n-octane.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 313-318 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention index ; Slope of log plot ; Homologous series ; Partition coefficient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The slope of the n-alkane log plot dt′R/dnc (t′R=adjusted retention time; nc=carbon number) for a stationary phase can be used to obtain the retention index of an unidentified substance in a chromatogram containing only one peak with a known retention index, or to predict the retention time of a substance from that of a different homolog in the same series. It can also be used to translate retention indices into relative retention time, partition coefficient or specific retention volume. Published values of the slope are collected and critically evaluated. Equations are deduced that predict its approximate value at a specified temperature given the value at only one other temperature.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 393-396 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Separation of optical isomers ; Chirasil-Val capillary columns ; Amino acid esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary D,L-amino acids were derivatized with (+), (±)-2-butanol or N-trifluoroacetyl-L-prolyl chloride (L-TPC) and then chromatographed. Four optical isomers were separated on a Chirasil-Val capillary column. By this method, the concentration of optical impurities arising from the commercial optically active reagents can be determined. The observed abnormal elution orders of enantiomeric amino acid esters may be caused by a selective intermolecular force.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Essential oils ; Evaporation rate ; Perfume composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple method was developed for the determination of the evaporation rate of essential oils and perfumery composition using gas chromatography with temperature programming. The volatility of 19 essential oils and 17 perfumery composition was evaluated. The method is useful for different comparative measurements.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 598-602 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Capillary columns ; Steroid profiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Steroid conjugates are hydrolysed enzymatically using β-glucuronidase after extraction from urine using a solid phase extraction cartridge. After hydrolysis the free steroids are removed from the matrix, again utilising solid phase extraction. Derivatisation of the free hydroxyl groups using Hydrox-Sil AQ produces the respective TMS ethers which are extracted into hexane, in which solvent they are stable for many days. Capillary GC analysis with flame ionisation detection produces a profile of the steroids present in the sample. This technique is suitable for following changes in the urinary excretion profiles of patients undergoing investigation for a variety of steroid production-related diseases.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 609-612 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography ; Triglyceride composition of grapes ; Identification system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The triglyceride composition of the Tempranillo grape (Vitis vinifera) has been examined by a combination of HPLC and GLC. To identify the triglycerides, equations were applied relating log k′ with the molecular variables: equivalent carbon number, chain length and number of double bonds in each of the fatty acids in the glycerides. Ten triglycerides were found, the principal ones being trilinolein (35.75%), dilinoleyl-olein (21.03%) and dilinoleyl-palmitin (17.02%).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 655-658 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Structure-retention relationships ; Connectivity indices, topological indices ; Alkenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Retention indices of different alkenes are correlated with connectivity and topological parameters. The appropriate statistically valid relations hips are derived and discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 735-736 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; α,ω-diiodoperfluoroalkanes ; Separation ; identification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The separation of α,ω-diiodoperfluoralkanes on a glass capillary column coated with OV-101 methylsilicone was investigated. Retention indices were determined at three temperatures (140, 150 and 160°C). The correlation between the retention indices and the boiling points of the investigated compounds was studied.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 731-734 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention Index (l) ; Temperature dependence of Retention Index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A linear dependence of (T−T1)/[1(T)−1(T1)] on temperature (considering the retention index 1(T1) at temperature T1 as a standard value) is derived. Both ther retention index at an assigned temperature and the temperature dependence of the retention index can be calculated from retention data measured at two temperature-programing rates.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 171-177 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; GC/MS analysis ; Polycyclic aromatic hydrocarbons ; Bituminous coal ; Brown coal ; Plant waxes ; Thermodesorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Polycyclic aromatic hydrocarbons (PAH) today are ubiquitous detectable constituents of recent sediments. The compounds are adsorbed on particulate emissions and are thus transferred to the environment. To date the analysis of PAH in sediments, dust samples and plant material is based mainly on the application of solvent-extraction methods followed by liquid chromatography and/or gas chromatographic separation of the extracts. An alternative approach for the analysis of PAH in solid samples such as coal, sediments, dust samples and plant waxes is shown in this contribution. A commercially available device for the analysis of volatile compounds present in solid matter is connected on-line to a GC/MS system. The device enables the thermal desorption of hydrocarbons at a temperature of 320°C. Subsequently, the hydrocarbons trapped on the initial part of the capillary column are analyzed by GC/MS. The application of mass chromatography provides the possibility of detection and quantitation of PAH in complex mixtures even when they coelute with other compounds. The sample amount required varies between 1 and 10 mg depending on the hydrocarbon content.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 229-233 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Glass capillaries ; Chirasil-Val ; Immobilisation ; Enantiomeric separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Immobilisation methods of the chiral silicone stationary phase Chirasil-L-Val have been studied. In addition to the standard techniques of radical-induced immobilisation with dicumyl peroxide and azo tert-butane, immobilisation was solely achieved by thermal treatment: conditioning at low flow-rates or under stop-flow conditions led to unexpectedly high immobilisation despite mild temperatures. The presence of water vapor in the carrier gas accelerated the immobilisation process. While up to 75% immobilisation was attainable with both ATB and thermal methods, immobilisation with DCUP did not exceed 50%, despite relatively high DCUP concentrations. Whilst all immobilisation methods were accompanied by varying degrees of racemisation at the chiral centre, it was possible to establish conditions that yielded a high immobilisation (in excess of 70%) with a negligible loss in enantiomeric selctivity. The immobilisation reactions also slightly affected the polarity of the stationary phase, reflected in a shift of the Kovats-Indices of amino acid derivatives and in the accompanying “Squalane-Effect”. With respect to immobilisation, racemisation and polarity shift, thermal immobilisation with water-saturated carrier gas proved to be the optimum method.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Preparation of methyl esters ; Tetramethylammonium hydroxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Tetramethylammonium hydroxide in methanol has been proposed as a catalyst for preparing methyl esters of both free fatty acids and glycerides of fats. Nevertheless, procedures normally recognized as suitable can be inadequate when the fat under study contains noticeable amounts of low relative molecular mass esters. The method using tetramethylammonium hydroxide has been examined and modified in order to analyze milk fats by capillary GC. The pyrolysis methylation of free fatty acids in capillary injectors has been also studied. The modified method was satisfactory for both neutral and acid milk fats.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Multi-chromatography ; Selectivity tuning ; Column combination ; Theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The evolution of the use of mixed phases or serial column combinations is outlined, leading to systems with fixed-length columns to be used in selectivity tuning (“multi-chromatography”). The difference between multi-chromatography and multi-dimensional gas chromatography is outlined. After discussing the system used in subsequent work, the fundamental relationships of multi-chromatography are detailed. Among the basic relationships the additivity of retention data, the relationship between the individual and composite capacity factors and the relative retentivity serving as the fundamental parameter of a multi-chromatography system are discussed. The relative retentivity is derived as a function of gas holdup times, pressures, and average velocities or flow rates. Finally, the relationships between individual vs. composite relative retention, efficiency, and resolution values are deduced.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Coated porous polymers ; Partition coefficients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Following previous work on the solute-stationary phase-adsorbent interaction phenomena associated with the use of Chromosorb 101 support in gas chromatography, the retention of different polarity compounds on columns of Ethofat, squalane and Fractonitril VI on Chromosorb 102 has been studied. The experimental partition coefficients in these three liquid phases have been compared with those ones obtained earlier on Chromosorb 101 and Chromosorb P. The values have been related to the geometry of the support surface and the different coating of the liquid phases by scanning electron microscopy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 21 (1986), S. 149-151 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention indices ; Comparison of data ; Alkenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Gas chromatographic retention indices for 47 C5 to C8 alkenes on OV-101 dimethylsilicone at 50 and 70 °C were determined within a standard deviation of 0.3i.u. Data obtained on OV-101 are compared with those measured on squalane. The comparison of the retention index and dl/dT values from both columns is presented as linear regression equations with correlation coefficients greater than 0.98.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 21 (1986), S. 157-160 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Alkylation ; Carboxylic acids ; Urine analysis ; Micelles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Carboxylic acids can be converted to their methyl esters in an aqueous sample which contains no organic solvent. The reaction appears to be assisted by the presence of a quaternary ammonium salt surfactant. The procedure is best described as a pseudo-organic phase, or micelle-like, reaction. The important experimental variables have been optimized by Simplex procedures. The reaction proceeds in 80–100% yield, for common carboxylic acids, at room temperature in less than one hour. This reaction is superior to existing two-phase extractive alkylation procedures.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Coated porous polymers ; Adsorption phenomena ; Surface areas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The behaviour of Chromosorb 101 and Chromosorb 102 supports coated with Ethofat 60/25, squalane and Fractonitril VI is compared. The adsorption constants of different solutes of varying polarity on these packings were calculated as well the surface areas for Chromosorb 102. The validity of the proposed equation used for correcting the specific surface areas of Chromosorb 102 for the molar volumes of each solute and the solubility parameters of the compounds, adsorbent and liquid phases is shown.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Ethylene oxide ; Active charcoal tubes ; Pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Air sampling of ethylene oxide on active charcoal tubes followed by GC analysis is a frequently proposed method. This paper studies just to what extent it can be used, defining its limitations (concentration range, influence of ambient temperature and relative humidity), which are seldom taken seriously into account. This method proves inadequate to determine low pollution levels, i.e. around 2 mg m−3.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 22 (1986), S. 333-336 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Split sampling ; PTV-sampling ; Discrimination ; Quantitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Parallel studies on split-sampling and PTV-sampling procedures have been made to highlight the difficulties in quantitative analysis for capillary columns. Parameters such as total sample amount, carrier gas and packing material used for the injector glass insert were studied. The results clearly demonstrate the importance of optimizing all experimental parameters which give rise to discrimination effects during injection.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 21 (1986), S. 538-540 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Micropacked column ; Milk ; Carbohydrate quantification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A gas chromatographic method using a micropacked column is described for the analysis of lactose, galactose, lactulose and epilactose in processed milks. The method is evaluated for precision and accuracy using phenyl-β-glucoside as an internal standard. Recoveries near 100% were found for lactulose concentrations higher than 0.1 mgml−1, showing coefficients of variation from 5.9 to 9.4%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Glass capillary columns ; Pre-treatment of column surface ; n-Octadecanol films
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The properties of n-octadecanol films on bare surface of glass capillary columns, leached with hydrochloric acid, HMDS treated and covered with BaCO3 have been investigated. Using the “inverse” gas chromatography method it was found that the structure of the n-octadecanol film distinctly depends on the glass surface preparation. The influence of the properties of the treated glass surface was particularly strong on the structure and properties of the n-octadecanol monolayer directly adjacent to the column wall.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 22 (1986), S. 329-332 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Esterification in aqueous solution ; n-propyl esters of C1−C22 fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary C1−C22 carboxylic acids have been esterified in aqueous solution with n-propanol. Gas chromatographic analyses have been performed from a single chromatogram. It has been proven that esterification in the concentration range of [H2O]/[n-PrOH]=0.022–8.45 can be utilized for the quantitative determination of these carboxylic acids. The presence of water does not interfere in the range of [H2O]/[n-PrOH]=0.22–1.27. In the cases of [H2O]/[n-PrOH]〉1.27, anhydrous sodium sulfate has been used for binding the water, in an amount of [Na2SO4 anh.]/[H2O]〉0.7.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    ISSN: 1612-1112
    Keywords: Gas chromatography ; (S)-(+)-Naproxen ; Amino acid methyl esters ; Resolution of diasteroisomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A GC method has been elaborated for the separation of enantiomers of some amino acid methyl esters after derivatization with activated (S)-(+)-naproxen. Nine amino acid ester paris were completely resolvede in a single run on a fused silica capillary column.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 993-998 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; HPLC system ; Micropacked column ; Organic mobile phase ; UV detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Retention behaviours of aromatic hydrocarbons were examined by using the vapour of an organic substance as the mobile phase and silica gel as the stationary phase. Gas chromatographic separation of aromatic hydrocarbons was demonstrated by using a system comprising a liquid chromatographic (LC) pump, a micropacked column for LC, a column oven and a UV detector.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention index ; Hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention of hydrocarbons present in the C5 pyrolysis fraction of gasolines on the stationary phases squalane and methylsilicone oil JXR at 30, 40 and 50°C was investigated by capillary gas chromatography. The unified retention indices of the hydrocarbons were also calculated on squalane. The retention indices obtained on these two phases were interrelated and the quantitative relationship with the structure of the solutes was studied. Equations based on the unified retention indices calculated on squalane and some selected structural elements of the solutes permit the calculation of their retention on methylsilicone with sufficient accuracy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Fused-silica capillary micro-packed columns ; Serial columns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary For the first time gas chromatographic characteristics of fused-silica capillary micro-packed columns consisting of two segments (i.e., serial columns) and packed with two different particle size fractions of the same sorbent have been investigated. The height equivalent to a theoretical plate (HETP) and the specific separation number vs. carrier gas velocity dependence has been studied. The expediency of empolying serial columns in which the segment containing the finer sorbent fraction is located near the column outlet has been theoretically and practically expalined. Serial columns with such an arrangement of the two segments show a better performance from the view point of efficiency and mass transfer coefficient.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 589-592 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Hold-up time determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary New versions are suggested for the gas hold-up time calculation in gas chromatography. The results are compared with those obtained by using other methods. The advantages of the suggested ways of calculation are pointed out.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 621-626 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Pre-column photolysis ; Halogenated hydrocarbons ; Identification of photolysis products ; Reaction mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Photodecomposition of chloro- and bromoderivatives of saturated, unsaturated and aromatic hydrocarbons has been studied under flow conditions using reaction gas chromatography. The photodegradation products were separated on a column coated with squalane and identified by comparing the measured retention data with those of standards and published retention indices, The results can be used to clarify the decomposition of such compounds.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 725-730 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Structure-retention correlation ; Kováts retention index ; Alkylaromatics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Relative retention data and Kováts retention indices were measured for several hydrocarbons (mainly for alkylbenzenes) on dinonylphtalate and polyethylenelycol 4000 stationary phase. Correlations were searched between these retention data and the following physical (boiling point, molrefraction, molvolume) and topological (connectiviity index and general index of molecular complexity) properties of solutes. The best fitting equations was choosen among more than 150 equations involving linear, quadratic, exponential, two variables linear and quadratic dependence of retention data and the properties mentioned as well as their inverses.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 817-821 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Water analysis ; Macroreticular polymeric adsorbent resins ; Herbicides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the determination of 3-phenyl-4-hydroxy-6-chloropyridazine in potable water. The method is based on isolation and enrichment by passing the water sample through a column of macroreticular polymeric adsorbent resin, concentration, derivatisation with pentafluorobenzoyl chloride and GC measurement with a N-specific detector. The individual experiments for establishing the working conditions, especially the adsorption characteristics of different types of resin, are described. The highest enrichment efficiency is obtained with the methacrylate-type resin XAD7. In field-sampling experiments a 10cm column yields 57% recovery at 100mLmin−1 flow rate, 0.3 ppb concentration level and 1 L sample volume. The method is completely documented; performance data are a detection limit of 0.07 μg L−1 and a mean recovery of 75% at the 0.3 ppb level.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Liquid crystals ; Thermodynamic properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Thermodynamic properties of 22 solutes at infinite dilution have been determined in the smectic, nematic and isotropic mesophases of 4,4′-bis(heptyloxy)azoxybenzone. The thermodynamic properties are discussed in relation to the solute-solvent (liquid crystal) interactions as conditioned by the degree of order in the liquid crystal.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Perhalogenated compounds ; Relative retentions ; Identification by interpolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Separation of perhalogenated compounds resulting from thermolysis, photolysis or radiolysis of mixtures of halogens in carbon tetrachloride was carried out by programmed temperature gas chromatography. Plots of relative retentions (to CBr4) vs the number of bromine atoms present for known compounds of the general formula CxBryClz (x=1 and 2; y+z=4 or 6) gave three linear correlations (all with r〉0.99). These correlations permitted projections of the identities of reaction products for which no standards were available. These projections were later confirmed by CG-MS. *** DIRECT SUPPORT *** A0732166 00010
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    ISSN: 1612-1112
    Keywords: Gas chromatography ; On-line process analysis ; Injection of volatile compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A modified on-line liquid injection technique with rotary valves for gas chromatography has been developed. Applications for the on-line analysis of 2-methylpropene, cyclohexene and 1-butene are described. All samples were loaded under pressure. The results obtained show excellent reproducibility with less than 0.1% relative standard deviation (r.s.d.; n=6) for the peak areas measured. The method is particularly advantageous for samples containing both gas and liquid ccomponents at one bar.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Capillary columns ; Multi-chromatography ; Selectivity tuning ; Column combination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary As a follow-up to our previous publication (see ref. [1]) dealing with the experimental system and the fundamental relationships of multi-chromatography („polarity tuning”), the present paper deals with the operation, characteristics and performance of the experimental set-up, and presents experimental verification on the validity of the basic relationships. The possibilities of influencing and adjusting the range in which the capacity factor is changed by the proper selection of column parameters are outlined and the observed changes in the retention index demonstrated. Ways to optimize the relative retentivity to achieve the best possible resolution of multi-component mixtures is illustrated. Finally, the possibility of combining temperature-programmed operation with selectivity tuning in a multi-chromatography system is demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Macroporous silica ; Silica-adsorbent modification ; Low boiling halocarbons ; Analysis of water pollutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of the silica adsorbent Silochrom C-80 modified by a thin liquid stationary phase film is proposed for the gas chromatographic analysis of low molecular weight halocarbons. Such modified adsorbents are characterized by good retention of the volatile halocarbons and high selectivity with respect to halocarbons. The thermodynamic sorption characteristics of alkanes, chloroalkanes and chloromethanes on Silochrom modified by three liquid phases (Apiezon L, methylsilicone and polyethylene glycol 20M) and on Chromaton N with thick films of the same phases were studied. The heats of sorption (−ΔH) and free sorption energy changes (−ΔF) of these substances and the increments −Δ(ΔH) and −Δ(ΔF) per chlorine atom in the chloralkane molecule compared with n-alkanes with the same number of carbon atoms were determined. The “chlorine” retention indices of low molecular weight volatile halocarbons on three sorbents were determined to identify them in aqueous solutions using the electron-capture detector. The analysis of drinking water by this technique is demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 21 (1986), S. 697-700 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Methyl silicones ; Unified retention index ; Hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Gas chromatographic retention indices of 51 hydrocarbons were determined on OV-101 dimethylsilicone between 40 and 70°C. From the measured data the unified retention indices were calculated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Linear temperature programming ; Thermodynamic chracteristics ; Calculation of k PT ′ for LPTGC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple method has been elaborated to calculate capacity ratios under programmed-temperature conditions (k PT ′ ) from the thermodynamic characteristics determined for the given column under isothermal conditions and the parameters of programmed-temperature operations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 21 (1986), S. 110-112 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Nitrochlorobenzene isomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An efficient, reproducible and rapid gas chromatographic method for the analysis of nitrochlorobenzenes has been described in this paper. The method uses FFAP as stationary phase and 3,4-dichloronitrobenzene as internal standard. The total analysis time of the method is less than 15 minutes with a coefficient of variation ranging from 0.41% to 1.19% for different levels of three isomers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Ethylene oxide ; HBr-treated charcoal tubes ; Pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Air sampling of ethylene oxide on HBr-treated charcoal tubes followed by capillary GC analysis of the 2-bromoethanol produced allows pollution control evaluation for concentrations ranging from 0.2 to 20 mgm−3. The adequacy of the method is assessed taking into account ambient temperature and relative humidity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 21 (1986), S. 305-311 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Headspace analysis ; Capillary columns ; Trace analysis ; Cryogenic trapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary When headspace gas chromatography utilizing capillary columns is used for trace analysis, sample enrichment is often needed. This involves splitless sample injection of fairly large gas volumes and relatively long sampling times. As a result of this, the band of the sample vapor may be too large causing peak distortion and poor resolution. This problem can be easily overcome by the use of cryogenic trapping. While this can be accomplished by cooling the whole column to subambient temperature during sample introduction, a more convenient way is to utilize part of the first coil of the capillary column as a cryogenic trap. The paper discusses the theoretical background and instrumentation of cryogenic trapping and demonstrates the possibilities through a number of examples.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 22 (1986), S. 63-64 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Reid vapour pressure ; Stabilized crude oils ; C2−C5 hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new rapid method has been developed to determine Reid Vapour Pressure (RVP) for stabilized crude oils by gas chromatography. The quantity of light hydrocarbons dissolved in crude oil was measured directly by gas chromatographic analysis, while the RVP value was computed utilizing a new correlation with this quantity at constant temperature. A variety of crude oils were investigated and the results revealed the accuracy of this method.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 22 (1986), S. 278-282 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Mixed phases ; Chlorinated C1−C3 hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method to establish the optimum composition of mixed stationary phases used in GC is given for the case when only the retention times on the individual phases are known. The method has been empirically tested for the resolution of chlorinated C1−C3 hydrocarbons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Nitrogen-selective detector ; Flash methylation ; Morphine ; Blood analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simplified gas chromatographic method for the rapid determination of morphinn in rat and human blood is described. After single extraction, morphine was reconstituded in trimethylanilinium hydroxide and introduced directly into a gas chromatograph equipped with a nitrogen specific flame ionization detector. Limits of detection were 0.5μg/ml for either water or blood solutions. Analytical recoveries of morphine, added to either water or blood were 88±6 and 90±3% $$(\bar x \pm SD)$$ , respectively, when compared with morphine dissolved in methanol. The between-run coefficients of variation were 5.0 and 5.4% for water and blood, respectively, over the range of 0.5–32.2μg/ml, whereas the within-run coefficients of variation at 1μg/ml were 8.1 and 7.9%, respectively. The application of the method to an in vivo animal experiment is demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 87-90 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Free acids in cheese ; Tetramethylammonium hydroxide soaps ; Packed and capillary columns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A rapid gas chromatographic method for the analysis of individual free fatty acids (FFA) in cheese has been developed. Lipds were extract from a cheese paste acidified with diethyl ether and tetramethylammonium hydroxide (TMAM) was used for converting the FFA to TMA-soaps, which are transformed to methyl esters in the chromatographic injector. The effect of lactic acid was determined. The reproducibility of the method was studied and the coefficient of variation for the total FFA was found to be 2.2%. Recovery of individual FFA was in the range 87 to 106%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Flame ionisation detector ; Perhalogenated compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In the determination of several perhalogenated compounds after gas chromatographic separation on an Apiezon L column, using a flame ionization detector, all the compounds tested gave linear area-mass plots although the coefficients observed do not lead to extrapolations which would permit quantitation of perhalogenated compounds for which no standard is available. Of the compounds tested, dibromodichloromethane, tetrachloroethene and tetrabromoethene gave good linear correlations of area ratio-mass ratio (using n-decane as the internal standard). Bromotrichloromethane and tetrabromomethane gave continuously curving area ratio-mass ratio plots which were very reproducible and could be used for graphical interpolation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 21 (1986), S. 397-401 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention time extrapolation ; Retention time interpolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An empirical method of extrapolating and interpolating gas chromatographic retention times obtained at three equally spaced isothermal temperatures is described. The accuracy of the method was evaluated from retention time data obtained using packed glass columns. A procedure for constructing retention time tables for homologous series and the derivation of an equation for calculating retention times as a function of temperature is also presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 453-454 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Reversed-flow technique ; Polymer activities ; Polymer interaction parameters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The reversed-flow, gas-chromatographic method for measuring activities and activity coefficients in binary liquid mixtures is now extended to the determination of activity coefficients of the solvent in polymer-solvent systems over the whole range of polymer concentration, as well as for the calculation of Flory-Huggins interaction parameters. The parameters found by the present method are compared with those determined by other techniques or calculated theoretically.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Glass capillary columns ; Bile acids ; Hexafluoroisopropyl esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A modified gas chromatographic glass capillary technique for determination of five major bile acids (Cholic acid: CA, Chenodeoxycholic acid: CDCA, Deoxycholic acid: DCA, Lithocholic acid: LCA and Ursodeoxycholic acid: UDCA) has been developed after preliminary extraction with XAD-2 resin. Enzymatic hydrolysis prevents the formation of interferring degradation products. Ether extraction with centrifugation eliminates water soluble interferring substances. Derivatization to hexafluorpropyl- instead of methyl esters results in better separation, shortens analysis time and prolongs the life span of the column.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 547-559 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Liquid column chromatography ; Process scale separations ; Review
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The relative merits of large scale gas chromatography (GC) and high performance liquid chromatography (HPLC) have not been reviewed for some considerable time. Although methodologies capable of manufacturing high efficiency (and hence cost effective) plant have existed for over a decade, commercial introduction has been remarkably slow. This has primarily been caused by confidentiality restrictions placed on equipment manufacturers, in turn severely limiting wide ranging applications data. These are necessary to raise potential end users confidence that both techniques offer viable large scale routes to separation and purification of mixtures as analysed by laboratory chromatographic methods. Considerable recent progress has been made with large scale HPLC plant, which has led to sufficient published data to make both technical and economic comparisons against GC possible.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 618-620 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Toluenesulfonic acid isomer distribution ; Ethyl toluenesulfonate isomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A gas chromatographic method for the determination of isomeric distribution in toluenesulfonic acid samples is described. The acids are transformed into the corresponding ethyl esters by reaction with triethyl orthoformate in toluene. The reaction mixture can be injected, without further purification, into the gas chromatograph. The separation is best performed on columns containing OV-210 or polyphenyl ether (6 rings) as the stationary phase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 691-693 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Al, Cr, Co and Fe acetylacetonates ; Capillary column separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention and resolution of simple mixture of Al(III), Cr(III), Co(III), and Fe(III) acetylacetonates were investigated on capillary columns coated with methyl and methyl phenyl silicones (OV-1 or OV-17) used as the stationary phase, at different column temperatures and carrier gas flow rates. Successful elution and good resolution were obtained only for the Al(III) and Cr(III) complexes, both under isothermal and programmed-temperature conditions; better resolution was observed on the column coated with OV 17.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 22 (1986), S. 271-274 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention index calculation ; Epoxides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The separation of C6 epoxides on a glass capillary column coated with OV-101 dimethylsilicone liquid phase was investigated. Retention indices were determined at four temperatures between 60 and 90°C. Linear regression equations permit the pre-calculation of the retention indices and the dI/dT values of the C6 epoxides from their properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 300-304 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Column liquid chromatography ; Polycyclic aromatic hydrocarbons ; Phenolic compounds ; Air pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An improved procedure for the determination of the less volatile air pollutants of recycled closed atmospheres by activated carbon-Soxhlet extraction is proposed. After total treatment of desorbate, PAH determination is then accomplished by RP-HPLC using both adsorptiometric and fluorimetric UV detection; phenolic compounds are determined by GC-MS. This technique is suitable for very low levels of PAH and phenolic compounds.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 34-36 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Gas analysis in halogen lamps ; Sampling device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new type of gas sampling device was constructed to improve the analysis of the gas in halogen lamps. Low levels of gases such as O2, CH4, C2H4 and CH3Br could be determined by the techniques worked out.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 413-416 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Gas analysis in incandescent lamps ; Gas chromatographic determination of O2 impurity in argon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A sensitive GC method was developed to analyse O2 (∼10–400ppm) in argon, by using Ar as carrier gas. A sampling method was developed for lamp analysis, and the O2 impurity content in the gas filling of incandescent lamps was measured. The results of the GC and MS measurements were in good agreement.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...