Supercritical fluids chromatography using

Cyclopentadiene oligomers up to octamers can be effectively analy2ed and quantified by supercritical fluid chromatography using a chemically bonded methyl siUcone capillary column. 

Figure 12.23 SFC-SFC analysis, involving a rotaiy valve interface, of a standard coal tar sample (SRM 1597). Two fractions were collected from the first SFC separation (a) and then analyzed simultaneously in the second SFC system (h) cuts a and h are taken between 20.2 and 21.2 min, and 38.7 and 40.2 min, respectively. Peak identification is as follows 1, tii-phenylene 2, chrysene 3, henzo[g/ i]perylene 4, antliracene. Reprinted from Analytical Chemistry, 62, Z. Juvancz et al, Multidimensional packed capillary coupled to open tubular column supercritical fluid chromatography using a valve-switcliing interface , pp. 1384-1388, copyright 1990, with permission from the American Chemical Society.

Figure 12.24 Schematic diagram of the multidimensional packed capillary to open tubular column SFC-SFC system. Reprinted from Analytical Chemistry, 62, Z. Juvancz et al., Multidimensional packed capillary coupled to open tubular column supercritical fluid chromatography using a valve-switching interface , pp. 1384-1388, copyright 1990, with permission from the American Chemical Society.

Supercritical fluid chromatography uses detectors from both liquid chromatography and gas chromatography. A summary of detection systems used in supercritical fluid chromatography has been documented [24]. 

Svensson, L.A. and Owens, P.K., Enantioselective supercritical fluid chromatography using ristocetin A chiral stationary phases. Analyst, 125, 1037, 2000. 

ViUeneuve, M.S., Anderegg, R.J. Analytical supercritical fluid chromatography using fully automated column and modifier selection valves for the rapid development of chiral separations. J. Chromatogr. A 1998, 826, 217-225. 

Supercritical fluid chromatography using chiral stationary phases... 

Kaida, Y. and Okamoto, Y. (1992) Optical resolution by supercritical fluid chromatography using polysaccharide derivatives as chiral stationary phases, Bull. Chem. Soc. Jpn. 65, 2286-2288. 

Good reproducibility has been reported for capillary supercritical fluid chromatography using a direct injection method without a split restrictor. This method (Fig. 1.2(b)) utilises a rapidly rotating internal-loop injector (Valeo Inst. Switzerland) which remains in-line with the column for only a short period of time. This then gives a reproducible method of injecting a small fraction of the loop into the column. For this method to be reproducible the valve must be able to switch very rapidly to put a small slug of sample into the column. To attain this a method called timed-split injection was developed (Lee Scientific). For timed split to operate it is essential that helium is used to... 

Figure 1.4. High-resolution separation of free fatty acids of indicated carbon numbers by supercritical fluid chromatography using a compressed C02 mobile phase at 170°C. Column is SO cm long fused silica capillary tube of 250 pm internal diameter. (Courtesy of Frank J. Yang.)...

Herbreteau, B., Lafosse, M., Morin-AIIory, L., and Dreux, M. 1990. Analysis of sugars by supercritical fluid chromatography using polar packed columns and light-scattering detection. Journal of Chromatography, 505 299-305. 

Supercritical fluid chromatography using carbon dioxide as the eluent is often carried out subcritically at 20°C or 25°C, because the more dense eluent... 

Berger, T.A. Deye, J.F. Separation of benzene poly-carboxylic acids by packed column supercritical fluid chromatography using methanol-carhon dioxide mixtures with very polar additives. J. Chromatogr. Sci. 1991, 29, 141. 

Villeneuve, M.S. Anderegg, R.J. Analytical Supercritical Fluid Chromatography Using Fully Automated Column and Modifier Selection Valves for the Rapid Development of Chiral Separations, 7. Chromatogr. A 826, 217-225 (1998). 

Supercritical fluid chromatography uses most of the same or slightly modified hardware. The greatest difference is that most of the normal liquid used as the mobile phase in HPLC is replaced with a liquefied gas, like carbon dioxide. Fluids other than carbon dioxide can be used, but for all practical purposes, SFC means C02-based chromatography. 

Separation of kavalactones was also achieved by supercritical fluid chromatography using methanol-modified carbon dioxide as the mobile phase. An optimal separation was achieved on either an amino or protein C4 column at 125 atm and 80 °C. Semipreparative separation of kavalactones was also obtained with two columns connected in series (Ashraf-Khorassani etal., 1999). A micellar electrokinetic chromatographic method with diode-array detection has also been developed for the identification and quantitative determination of the major kavalactones from extracts of P. methysticum... 

Mathiasson, L., J.A. Jonsson, and L. Karlsson. 1989. Determination of nitrogen compounds by supercritical fluid chromatography using nitrous oxide as the mobile phase and nitrogen-sensitive detection. J. Chromatogr. 467 61-74. 

Ashraf-Khorassani, M. Levy, J.M. Addition of modifier in supercritical fluid chromatography using a microhore reciprocating pump. Chromatographia, 1995, 40, 78-84... 

K.L. Williams, L.C. Sander and S.A. Wise, Comparison of Liquid and Supercritical Fluid Chromatography Using Naphthylethylcarbamoylated- 3-cyclodextrin Chiral Stationary Phases, J. Chromatogr. A, 746(1996)91. 

Juvancz, Z. Payne, K.M. Markides, K.E. Lee, M.L. Multidimensional packed capillary coupled to open tuhular column supercritical fluid chromatography using a valveswitching interface. Anal. Chem. 1990, 62, 1384—1388. 

Chester, T.L. Innis, D.P. Quantitative open-tubular supercritical fluid chromatography using direct injection onto a retention gap. Anal. Chem. 1995, 67 (17), 3057-3063. 

Gere, D., Board, R., Me Manigill, D. (1982) Parameters of supercritical fluid chromatography using HPLC columns. Hewlett-Packard PubI 43-5953-1641, Avondale. Pennsylvania. 7-15. 

Skaar, H., Norli, H.R., Lundanes, E., and Greibrokk, T. (1990) Group separation of crude oil by supercritical fluid chromatography using packed narrow bore columns, column switching, and backflushing. Journal of Microcolumn Separations, 2,222. 

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