Gas Chromatographic Data

530 Isopropyl Alcohol 1180 Benzoic Acid 1419 Methyl Hydroxybenzoate 

579 Methyl Ethyl Ketone 1205 2-Bromo-2-ethylbutyramide 1436 Nicotinamide 

1000 1017 Acepifylline Fluspirilene 1340 2-Bromo-2-ethyl-3-hydroxybutyr- amide 1547 Acetylcysteine Aminobenzoic Acid 

The values given are those of the tertiary bases or of trifluoroacetyl derivatives. 

6 Propane 7.3 Methyl Ethyl Ketone 20.3 Amyl Nitrite 

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P.J. Dunlop, C.M. Bignell, J.F. Jackson, D.B. Hibbert, Chemometric analysis of gas chromatographic data of oils from Eucalyptus species. Chemom. Intell. Lab. Systems 30 (1995) 59-67. K. Varmuza, F. Stangl, H. Lohninger and W. Werther, Automatic recognition of substance classes from data obtained by gas chromatography, mass spectrometry. Lab. Automation Inf. Manage., 31 (1996) 221-224. 

Gilbert, J., Shepherd, M. J., Wallwork, M. A., and Harris, R. G. (1981). Determination of the geographical origin of honeys by multivariate analysis of gas chromatographic data on their free amino acid content. /. Apicult. Res. 20,125-135. 

The net retention volume and the specific retention volume, defined in Table 1.1, are important parameters for determining physicochemical constants from gas chromatographic data [9,10,32]. The free energy, enthalpy, and. entropy of nixing or solution, and the infinite dilution solute activity coefficients can be determined from retention measurements. Measurements are usually made at infinite dilution (Henry s law region) in which the value of the activity coefficient (also the gas-liquid partition coefficient) can be assumed to have a constant value. At infinite dilution the solute molecules are not sufficiently close to exert any mutual attractions, and the environment of each may be considered to consist entirely of solvent molecules. The activity... 

These results are consistent with the gas chromatographic data. Also noted in the infrared spectra is an increase in the urea absorption at 1630 cm-1 as the temperature is increased. In this latter case, the free amine reacts with isocyanate (liberated by normal deblocking of a blocked isocyanate) to generate urea linkages). 

Gravimetric or infrared methods are often preferred for high-molecular-weight samples. These methods can even be used as a check on gas chromatographic data if it is suspected that high-molecular-weight hydrocarbons are present but are not being detected. 

Gas chromatographic data was obtained on a Tracor Model 220 gas chromatograph equipped with a Varian Model 8000 autosampler. The analysis column was a 1.7 m "U column, 4 mm id, filled with 3% SP-2250 packing (Supelco, Inc., Bellefonte, PA) held at 200 C. The injection temperature was 250 and the nitrogen carrier gas flow rate was 60 mL/min. The detector temperatures were 350 for electron capture and 190 for flame photometric. Detector signals were processed by a Varian Vista 401 which gave retention times and peak areas. 

Application of Pattern Recognition to High-Resolution Gas Chromatographic Data Obtained from an Environmental Survey... 

All astatohalobenzenes were identified by GLC their thermodynamic properties were estimated by extrapolative gas chromatographic data related to the corresponding dihalobenzene isomers 17, 99, 137, 138) (see Table V). 

Hippe et al. discussed numerical operations for computer processing of (gas) chromatographic data. Apart from a baseline correction method, a method of reco -tion of peaks is described. The relationship between the convexity of an isolated peak and the monotonic nature of its first derivative is used to find the most probable deflection points. The munber of maxima and shoulders are used for a decision if the segment of the chromatogram contains an isolated peak or an unresolved peak complex. The number of shouders and maxima determine the total number of component peaks. 

The various heterocyclic systems, their gas-chromatographic data (Kovdts indices), and the mass spectra are summarized in Table I. 

Howard, S., and Rayborn, G. H. (1980). Deconvolution of Gas Chromatographic Data. NASA Contractor Report CR-3229. 

Another significant application of GC is in the area of the preparation of pure substances or narrow fractions as standards for further investigations. GC also is utilized on an industrial scale for process monitoring. In adsorption studies, it can be used to determine specific surface areas (30,31). A novel use is its utilization to carry out elemental analyses of organic components (32). Distillation curves may also be plotted from gas chromatographic data. 

Qualitative analysis by gas chromatography (GC) in the classical sense involves the comparison of retention data of an unknown sample with that of a known sample. The alternate approach involves combination and comparison of gas chromatographic data with data from other instrumental and chemical methods. 

The activity coefficient at infinite dilution may be obtained directly from gas chromatographic data. 

The equilibrium constant can be derived from free energy considerations of gas chromatographic data. It may also be obtained directly from the measurement of all concentrations at the specified temperature by selection of a column that can separate each component and by a quantitative method of detection. 

Furthermore, it has been shown that activation energies may be derived from gas chromatographic data. (Activation energy is an empirical constant with units of energy which can be visualized as the quantity of energy needed before a reaction may begin.)... 

Another conclusion arising from the data in Table III is that the largest carbon loss takes place during the first reaction hours (less than 15), when the synthesis is probably intensely competitive because of the release of volatile derivatives. (Some gas chromatographic data indicate decarboxylation of the polyester). The polymer becomes more and more thermostable as reaction time increases. 

When volatile data are compared to sensory blandness scores as discussed above, it becomes apparent that the measurements do not totally agree. DSF was subjectively evaluated as being rather bland in taste while SPC was stronger. In contrast the objective gas chromatographic data would indicate otherwise. In all probability, certain volatile compounds in SPC at higher levels than DSF (Peaks 7, 18, 20, 23, 24) are responsible for these differences. 

O. E. Schupp and J. E. Lewis (eds.), Compilation of Gas Chromatographic Data, 2d ed., ASTM Special Publication AMD-25A and Supplement 1, Publication AMD-25A S-l, American Society for Testing and Materials, Philadelphia, 1967 and 1971. 

Caydou, E.M. and Randriamiharisoa, R. (1987) Multidimensional analysis of gas chromatographic data, application to the differentiation of clove bud and clove stem essential oils from Madagascar. Perfumer and Flavorist 12, 45-51. 

A total of 24 burns were sampled and analyzed, using the methods described above. Typical qualitative analytical results for two successful burns appear in Table X. The compounds were identified on the basis of both mass spectral and gas chromatographic data (J5, 6). The notations L, M, and... 

W. O. Kwan, B. R. Kowalski, Pattern recognition analysis of gas chromatographic data. Geographic classification of wines of Vitis vinifera cv. Pinot Noir from France and the United States, J. Agric. Food Chem., 28 (1980), 356-359. 

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