Gas chromatography programmed temperature

The odor concentrates were separated by temperature-programmed gas chromatography on a 20% Carbowax 20M column. Typical chromatograms obtained from the distillate—i.e., the odor concentrate isolated... 

Figure 3.8 shows an example dataset of mixed hydrocarbons used as a petrochemical feedstock. These are straight-run naphthas which consist of a wide range of alkane, alkene, aromatic and naphthenic hydrocarbons, mainly in the range of C4-C9. The conventional analytical method for naphtha analysis is temperature-programmed gas chromatography (GC), which can provide a full analysis including C-number breakdown, but which is rather slow for process optimisation purposes. 

Bridie et al. [27] have studied the solvent extraction of hydrocarbons and their oxidative products from oxidised and non-oxidised kerosine-water mixtures, using pentane, chloroform and carbon tetrachloride. Extracts are treated with Florasil to remove non-hydrocarbons before analysis by temperature programmed gas chromatography. From the results reported it is concluded that, although each of the solvents extracts the same amount of hydrocarbons, pentane extracts the smallest amount of non hydrocarbons. Florasil effectively removes non hydrocarbons from pentane extracts, but also removes 10-25% of aromatic hydrocarbons. However, as the other solvents are less susceptible than pentane to treatment with Florasil, pentane is considered by those workers to be the most suitable solvent for use in determining oil in water. 

Iverson, J.L. and Sheppard, A.J. (1986) Determination of fatty acids in butter fat using temperature-programmed gas chromatography of the butyl esters. Food Chem., 21, 223-234. 

The experimental details of the preparation of samples, the pulse-irradiation procedure, and the recording and analysis of data have all been described (6, 7, 9). Product analysis was done as previously described (9), using temperature programmed gas chromatography (25°C. to 230°C.) and a 2% Versamid-900 on silanized Chromosorb (white, acid washed, 60-80 mesh) column. 

If needed, increased sensitivity can be obtained for trimethylben-zenes, and the range can be extended to include the naphthalenes if the equilibrated gas is analyzed by temperature-programmed gas chromatography. Figure 3a shows an isothermal run of hydrocarbons dissolved in seawater from an excess of a Murban crude oil. Figure 3b shows a temperature-programmed run on a similar water sample. 

Dry distillation and gas phase separation of technetium oxides from oxides of rhenium, osmium, iridium, and ruthenium by temperature-programmed gas chromatography using O2 as reactive gas was reported [109]. Furthermore, the separation of technetium chloride (TeCU) from volatile chlorides of numerous elements by thermo-chromatography combined with complex formation was investigated. The separation tube had a temperature gradient from 600 to 25 °C and was coated with KCl, CsCI, NaCl, and BaClj [HOj. 

In subsequent publications further refinements of this system were described [9], [14], These included a reduction in both column and sample size to improve resolution. The column dimensions were reduced to 7 x 0.9 cm and the sample size of polymers was 20 mg loaded in 3 ml of solvent. A temperature programmed gas chromatography oven was used to replace the less convenient oil bath to provide a more reproducible temperature gradient. The detector was also changed to an infra-red (IR) detector which provides adequate sensitivity with much improved base-line stability due to the relative insensitivity of the IR detector to temperature fluctuations. The resultant TREF curves clearly demonstrated the much improved resolution achievable by these refinements. 

Barry, E.F. Grob, R.L. Columns for Gas Chromatography Performance and Selection.Wiky New York, 2007. Blumberg, L.M. Temperature-Programmed Gas Chromatography. Wiley New York, 2010. 

Polyoxymethylene oligomers have been separated by temperature programmed gas chromatography." ... 

METHOD 29 - DETERMINATION OF HYDROCARBON IMPURITIES IN STYRENE MONOMER, TEMPERATURE-PROGRAMMED GAS CHROMATOGRAPHY. 

Determination of hydrocarbon impurities in styrene monomers. Temperature programmed gas chromatography... 

Bianchi, E, Careri, M., Mangia, A., and Musci, M. (2007) Retention indices in the analysis of food volatiles in temperature-programmed gas chromatography Database creation and evaluation./. Sep. ScL, 30, 563-572. 

Kavanagh, P. E., Balder, D., and FrankUn, G. (1999) Estimation of retention times of homologous series in temperature programmed gas chromatography. Chromatographia, 49, 509-12. 

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