Gas‐chromatographische Charakterisierung organischer Verbindungen. Teil 1: Retentionsindices aliphatischer Halogenide, Alkohole, Aldehyde und Ketone
TL;DR: In this article, a simple relation exists between the retention index of a compound on a non-polar stationary phase and its boiling point, which is defined as the ratio of the boiling point of the compound to its retention index.
Abstract: For the characterization of organic substances in gas chromatography a number termed «retention index» is proposed. A simple relation exists between the retention index of a compound on a non-polar stationary phase and its boiling point.
Citations
More filters
TL;DR: The equation given by Kovats for the calculation of the retention index in case of isothermal operation is transformed to a more general form to include also the case of linear temperature programmed operation and gives the same retention index for both ways of operation.
5,192 citations
TL;DR: In this article, some 900 Kovats' indices of 400 individual compounds on methyl silicone (dimethyl polysiloxane) and/or Carbowax 20M liquid phases are summarized from the general literature.
2,118 citations
TL;DR: The composition of seven technical PCB-mixtures (Aroclor [Monsanto, USA] und Clophen A [Bayer, FRG]) has been investigated by high-resolution thin-film glass capillary gas chromatography with electron-capture detector.
Abstract: The composition of seven technical PCB-mixtures (Aroclor [Monsanto, USA] und Clophen A [Bayer, FRG]) has been investigated by high-resolution thin-film glass capillary gas chromatography with electron-capture detector. Methylpolysiloxane (SE 30) and purified Apiezon L have been used as liquid phases. Identification of the single PCB components has been performed by comparison of their retention indices with those of polychlorinated biphenyls defined by synthesis or with values calculated from retention index increments. For marking the individual PCB compounds a systematic numbering has been used.
1,303 citations
TL;DR: The FiehnLib libraries can be used in conjunction with GC/MS software but also support compound identification in the public BinBase metabolomic database that currently comprises 5598 unique mass spectra generated from 19,032 samples covering 279 studies of 47 species.
Abstract: At least two independent parameters are necessary for compound identification in metabolomics. We have compiled 2 212 electron impact mass spectra and retention indices for quadrupole and time-of-flight gas chromatography/mass spectrometry (GC/MS) for over 1 000 primary metabolites below 550 Da, covering lipids, amino acids, fatty acids, amines, alcohols, sugars, amino-sugars, sugar alcohols, sugar acids, organic phosphates, hydroxyl acids, aromatics, purines, and sterols as methoximated and trimethylsilylated mass spectra under electron impact ionization. Compounds were selected from different metabolic pathway databases. The structural diversity of the libraries was found to be highly overlapping with metabolites represented in the BioMeta/KEGG pathway database using chemical fingerprints and calculations using Instant-JChem. In total, the FiehnLib libraries comprised 68% more compounds and twice as many spectra with higher spectral diversity than the public Golm Metabolite Database. A range of unique c...
1,153 citations
TL;DR: A platform that integrated the chemical analysis, including identification and relative quantification, data reduction, and quality assurance components of the process enabled the high-throughput collection and relative quantitative analysis of analytical data and identified a large number and broad spectrum of molecules with a high degree of confidence.
Abstract: To address the challenges associated with metabolomics analyses, such as identification of chemical structures and elimination of experimental artifacts, we developed a platform that integrated the chemical analysis, including identification and relative quantification, data reduction, and quality assurance components of the process. The analytical platform incorporated two separate ultrahigh performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS2) injections; one injection was optimized for basic species, and the other was optimized for acidic species. This approach permitted the detection of 339 small molecules, a total instrument analysis time of 24 min (two injections at 12 min each), while maintaining a median process variability of 9%. The resulting MS/MS2 data were searched against an in-house generated authentic standard library that included retention time, molecular weight (m/z), preferred adducts, and in-source fragments as well as their associated MS/MS spectra for all molecul...
1,139 citations
References
More filters
TL;DR: Modifications necessary to the theory of Martin & Synge (1941) to allow for the compressibility of the mobile phase are presented and the application of the gas-liquid partition chromatogram to the separation of volatile fatty acids is described.
Abstract: Industry has long used charcoal or other solid absorbents in columns for cleaning gas streams or for solvent recovery, and more recently Turner (1943), Claesson (1946), Glueckauf, Barker & Kitt (1949), Phillips (1949) and Turkel'taub (1950) have used charcoal in gas chromatograms for the analysis of hydrocarbons and esters. Gas-liquid scrubbing columns have been used in industry for many years but, though Martin & Synge (1941) suggested the use of gas-liquid partition chromatograms for analytical purposes, no work has been reported along these lines. This paper presents modifications necessary to the theory of Martin & Synge (1941) to allow for the compressibility of the mobile phase and describes the application ofthe gas-liquid partition chromatogram to the separation of volatile fatty acids. The separations obtainable by this method are essentially parallel to those obtainable by distillation, but good separations can be achieved much more easily and it is possible to work with very much smaller quantities. In fact, the lower limit of quantity of material used is determined only by the efficiency of detection. In general, far less trouble from azeotrope formation is to be expected, since the concentrations of the substances to be separated in the liquid phase are always low and it may be possible to choose a liquid phase which associates only with one component of the azeotrope. Work on a preparative scale, though theoretically possible, is likely to be inconvenient because of the bulk of the apparatus. The method of detection described here is acid-base titration, but many methods of detecting changes in the composition ofa gas stream could be used and it is intended in future publications to explore some of these, which should extend the range of application to all substances capable of being distilled at the pressure of a few mm. of mercury. In suitable cases the gas-liquid partition column has two principal advantages over the ordinary liquid-liquid partition column: (a) the low viscosity of the mobile phase allows relatively longer columns to be used with a corresponding gain in efficiency and (b) in general it is easier to detect changes in composition of a gas than of a liquid stream. A THEORY OF GAS-LIQUID PARTITION CHROMATOGRAPHY
1,513 citations
TL;DR: Analysis of the volatile amines present in Chenopodium vulvaria L. shows the presence of only ammonia and trimethylamine, compared with standard mixture ofmono-, di and tri-methylamines, which indicates a low concentration of ammonia in the plant.
Abstract: Fig. 6. Analysis of the volatile amines present in Chenopodium vulvaria L. Curve A: standard mixture ofmono-, diand tri-methylamines. Curve B: chromatogram of the amines present in an acid extract ofthe plant, showing the presence of only ammonia and trimethylamine. (Column length, 4ft.; liquid phase, hendecanol-iS% liquid paraffin (v/v); temp., 78 50; flow rate of nitrogen, 5.7 ml./min.; nitrogen pressure, 80 mm. Hg.)
110 citations
68 citations
17 citations