Supercritical fluid chromatography hydrocarbons

Figure 12.21 SFC-GC heait-cut analysis of chrysene from a complex hydrocarbon mixture (a) SFC ttace (UV detection) (b) GC trace without heait-cut (100% transfer) (c) GC ti ace of heatt-cut fraction (flame-ionization detection used for GC experiments). Reprinted from Journal of High Resolution Chromatography, 10, J. M. Levy et al., On-line multidimensional supercritical fluid chromatography/capillaiy gas cluomatography , pp. 337-341, 1987, with permission from Wiley-VCFI.

If simple sample pretreatment procedures are insufficient to simplify the complex matrix often observed in process mixtures, multidimensional chromatography may be required. Manual fraction collection from one separation mode and re-injection into a second mode are impractical, so automatic collection and reinjection techniques are preferred. For example, a programmed temperature vaporizer has been used to transfer fractions of sterols such as cholesterol and stigmasterol from a reversed phase HPLC system to a gas chromatographic system.11 Interfacing gel permeation HPLC and supercritical fluid chromatography is useful for nonvolatile or thermally unstable analytes and was demonstrated to be extremely useful for separation of compounds such as pentaerythritol tetrastearate and a C36 hydrocarbon standard.12... 

Fuoco et al. [539] has reported the analysis of priority pollutants in seawater using online supercritical fluid chromatography, cryotrap gas chromatogra-phy-mass spectrometry. Using this system polynuclear aromatic hydrocarbons and polychlorobiphenyls were measured in seawater with recoveries better than 75%. 

A paper has been published showing the use of the photoionization detector [26], Polyaromatic hydrocarbons are very sensitive using the photoionization detector and the levels detected did not break any new ground in terms of sensitivity. It did inspire HNS Systems (Newtown MA, USA), who market a photoionization detector, to try the detector with a capillary system, interfaced to a Lee Scientific 602 supercritical fluid chromatography (Lee Scientific, Salt Lake City, Utah, USA). 

Andersson P, Demirbuker M, Blomberg L. 1992. Quantitative hydrocarbon group- analysis of gasoline and diesel fuel by supercritical fluid chromatography. Journal of Chromatography 595(1-2) 301-311. 

J. L. Bernal, M. J. Nozal, L. Toribio, M. L. Serna, F. Borrull, R. M. Marce and E. Pocurull, Determination of polycyclic aromatic hydrocarbons in waters by use of supercritical fluid chromatography coupled on-line to solid-phase extraction with disks , J. Chromatogr. 778 321-328 (1997). 

PCB phase diagrams with carbon dioxide Effect of temperature and pressure on extraction of PCB and polyaromatic hydrocarbons Combination of solid-phase carbon trap with supercritical fluid chromatography for PCB, pesticides, polychlorodibenzo-p-dioxins and polychlorofurans... 

Microwave induced plasma mass spectrometry has also been used as a detector for supercritical fluid chromatography (SFC) [113] for the separation of halogenated hydrocarbons. The design of an SFC-MIP interface must ensure that the frit restrictor temperature remains at a high temperature to prevent condensation of analytes. Stainless steel transfer lines may be used. The frit restrictor should be connected to a length of deactivated fused silica capillary, inserted through the transfer line, and positioned flush with the aluminum MIP torch inset (Fig. 10.21). 

Supercritical fluid chromatography (SFC) with ELD, using CO2 or C02-MeOH as mobile phase, was applied to simultaneous determination of 11 priority phenols and 13 polycyclic aromatic hydrocarbons. Voltammetric measurements allow low-nanogram detection limits of reducible and oxidizable analytes, even if they elute simultaneously from the chromatographic column . SFC with MeOH-modified CO2 was performed under isobaric and pressure-programmed conditions, combined with ELD. LOD was 250 p,g of 2,6-dimethylphenol for oxidative ELD and 100 pg of 1,3-dinitrobenzene for reductive ELD . Various sorbents were investigated for SPE preconcentration prior to SFC 20 . 

Moyano, E., McCuUagh, M., Galceran, M. T., and Games, D. E., Supercritical fluid chromatography-atmospheric pressure chemical ionization mass spectrometry for the analysis of hydroxy polycyclic aromatic hydrocarbons, J. Chromatogr. A, 111, 167-176, 1997. 

Anacleto, J. E., Ramaley, L., Boyd, R. K., Ploeasance, S., QuiUiam, M. A., Sim, P. G., and Benoit, F. M., Analysis of polycychc aromatic compounds by supercritical fluid chromatography mass spectrometry using atmospheric-pressure chemical ionization. Rapid Commun. Mass Spectrom., 5, 149-155,1991. Mansoori, B. A., Isomeric identification and quantification of polycychc aromatic hydrocarbons in environmental samples by liquid chromatography tandem mass spectrometry using a high pressure quadrupole collision cell, Rapid Common. Mass Spectrom., 12, 712-728, 1998. 

See alsa Air Analysis Outdoor Air. Food and Nutritional Analysis Contaminants. Gas Chromatography Detectors. Luminescence Overview. Nitrosamines. Ozone. Phosphorus. Polycyclic Aromatic Hydrocarbons Determination. Environmental Applications. Sulfur. Supercritical Fluid Chromatography Ovenriew Applications. 

Overview. Polychlorinated Biphenyls. Polycyclic Aromatic Hydrocarbons Determination. Polymers Natural Rubber Synthetic Polyurethanes. Quality Assurance Quality Control Instrument Calibration Interlaboratory Studies Reference Materials Production of Reference Materials Method Validation Accreditation Clinical Applications Water Applications. Sample Handling Comminution of Samples Sample Preservation Automated Sample Preparation Robotics. Sampling Theory Practice. Solvents. Supercritical Fluid Chromatography Overview Applications. Vitamins Overview Fat-Soluble. 

Dressman, S.F. Simeone, AM. Michael, A.C. Supercritical fluid chromatography with electrochemical detection of phenols and polyaromatic hydrocarbons. Anal. Chem. 1996, 68, 3121-3127. 

The results for total saturates and aromatics from different class-type separations for these fuels were shown previously in Tables 1 and 2. The results in Table 5 provide a more detailed composition. Methods like supercritical fluid chromatography (SFC) and high performance liquid chromatography (HPLC) can only determine the aromatic subgroups (mono-, di-, and polyaromatics). We used these data to evaluate the reliability of hydrocarbon t)q)es determined by both EIMS and FIMS methods. In all cases there is a very good agreement between the methods. There are no independent techniques that would allow estimation of the MS performance... 

Norris, T. A. and Rawdon, M. G., "Determination of Hydrocarbon Types in Petroleum Liquids by Supercritical Fluid Chromatography with Flame Ionization Detection," Analytical Chemistry, Vol. 56, 1984, pp. 1767-1769. 

The combination of HPLC with GC can provide more detailed compositional information than either technique alone. Typically HPLC is used to separate a particular hydrocarbon group (saturates, mono-aromatics, di-aromatics) and transfer it to a high-resolution GC column that can resolve many of the individual compounds [4,5 ]. Supercritical fluid chromatography, (SFC), can be used instead of HPLC to make the primary separation [6 ]. These are rather sophisti-... 

A new method for hydrocarbon tjqie anal3 is using supercritical fluid chromatography is under development by ASTM Subcommittee D02.04 and should be available shortly. 

This test method covers the determination of the total amounts of monoaromatic and polynuclear aromatic hydrocarbon compounds in motor diesel fuels, aviation turbine fuels, and blend stocks by supercritical fluid chromatography (SFC). The range of aromatics concentration to which this test method is applicable is from 1 to 7S mass %. The range of polynuclear aromatic hydrocarbon concentrations to which this test method is applicable is from O.S to SO mass %. 

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