High temperature gas chromatography: The development of new aluminum clad flexible fused silica glass capillary columns coated with thermostable nonpolar phases: Part 1

Abstract

SummaryWith the simultaneous development of blank aluminum clad flexible fused silica glass capillary tubing capable of withstanding temperatures up to 5OO0C, coincident with a series of special high temperature methyl polysiloxane polymers, it was possible to produce for the first time, long lived fused silica capillary columns containing thin films of thermostable stationary phases which could be maintained isothermally at 400-425OC and temperature programmed to 425-440OC. The "bleed rate" here for a well conditioned column was 5 picoamperes or less. Under these circumstances, alkanes with carbon numbers in theC-90 toC-l00area wererapidlyand efficientlyeluted from these columns. By extrapolation here, one can easily detect certain compounds with boiling points in the 75OOC range. Since this type of capillary column was found to possess certain favorable properties, it was thought that it will soon replace the packed column and will probably be more popular than the borosilicate capillary column for many high temperature applications. Moreover, evidence has now accumulated which leads us to further believe that the majority of analyses of "high molecular weight" compounds performed by Supercritical Fluid Chromatography (SFC), utilizing very narrow bore fused silica capillary columns at several hundred atmospheres, can be much more simply, much more rapidly, much more economically, and much more efficiently accomplished by gas chromatography utilizing this new generation of high temperature capillary columns.

Petroleum Geochemistry: Concepts, Applications, and Results

“…The waxes which form typically contain a relatively high concentration of high molecular weight hydrocarbons above C 30 , and possibly up to C 100 , which may not be observable in the oils collected at the well-head − (Figure ). The study of higher molecular weight (C 40 ) hydrocarbons had been largely overlooked prior to the development of high-temperature gas chromatography (HTGC) columns , and supercritical fluid chromatography − which now permit characterization of hydrocarbons extending to the C 120 . ,

3 Waxes from four different wells in Oklahoma analyzed by high-temperature gas chromatography. If these samples had been analyzed by conventional gas chromatography, the components in the carbon number range above C 35 would not have been observed, and the seriousness of the problem resulting from the presence of these waxes would have been underestimated.

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Waxes in asphaltenes of crude oils and wax deposits

“…It was demonstrated repeatedly that high molecular weight nalkanes were concentrated in solid deposits formed in well equipment and pipelines (Philp et al 1995;Chouparova et al 2004). Moreover, the concentrations of high molecular weight paraffin hydrocarbons in oils, which are determined by high temperature gas chromatography (HTGC, one of the main methods for investigating hydrocarbon composition of oils) (Lipsky and Duffy 1986;Hawthorne and Miller 1987), are underestimated because of the poor solubility of the high molecular weight hydrocarbons in the solvent and the difficulty in eluting of & Yulia M. Ganeeva yuyand@yandex.ru such high boiling components even at 440°C, resulting in the bias of response toward the shorter-chain homologs (Philp et al 1995). Asphaltenes are the heaviest and most polar compounds in crude oils with the highest aromaticity and polarity.…”

Improvement of Simulated Distillation Methods by Gas Chromatography in Routine Analysis

“…For HTSD method, it is necessary to decrease the film thickness to 0.10-0.15 µm to elute the normal paraffin C 100 . In this case, the separation of light paraffins is not good and the method does not apply with samples containing light components below the normal paraffin C 10 . Figure 4 shows the chromatogram of a mixture of normal paraffins C 10 -C 100 .…”

“…Over the last 12 years, the use of capillary columns has become widespread [10][11][12][13][14][15]. ASTM D2887 has been up dated with these columns and a new precision determined better than with packed columns.…”