Carbon dioxide supercritical-fluid chromatography with

Hadj-Mahammed, M., Badjah-Hadj-Ahmed, Y., and Meklati, B.Y., Behavior of pol5nnethoxy-lated and polyhydroxylated flavones by carbon dioxide supercritical fluid chromatography with flame ionization and Fourier transform infrared detectors, Phytochem. Anal, 4, 275, 1993. 

H. Daimon and Y. Hirata, Direct coupling of capillary supercritical fluid chromatography with superaitical fluid extraction using modified carbon dioxide , J. High Resolut. Chromatogr. 17 809-813 (1994). 

Snyder et al. [253] compared supercritical fluid chromatography with classical sonication procedures and Soxhlet extraction for the determination of selected insecticides in soils and sediments. In this procedure the sample was extracted with carbon dioxide modified with 3% methanol at 350atm and 50°C. An excess of 85% recovery of organochlorine and organophosphorus insecticides was achieved. These included Dichlorvos, Diazinon, (diethyl-2-isopropyl-6-methyl 4-pyrimidinyl phosphorothioate), Ronnel (i.e. Fenchlorphos-0,0 dimethyl-0-2,4,5-trichlorophenyl phosphorothioate), Parathion ethyl, Methiadathion, Tetrachlorovinphos (trans-2-chloro-l-(2,4,5 trichlorophenyl) vinylchlorophenyl-O-methyl phenyl phosphoroamidothioate), Endrin, Endrin aldehyde, pp DDT, Mirex and decachlorobiphenyl. 

J.L. Janicot, M. Caude, and R. Rosset, Separation of opium alkaloids by carbon dioxide sub- and supercritical fluid chromatography with packed columns Application to the quantitative analysis of poppy straw extracts, J. Chromatogr., 437 351 (1988). 

S. Rokushika, K. P. Naikwadi, A. L. Jadhav, and H. Hatano. Polyacrylate liquid crystalline stationary phases in supercritical fluid chromatography with carbon dioxide mobile phase. Chromatographia, 22 209-212,1986. 

Upnmoor, D. and Brunner, G. (1992) Packed colunrn supercritical fluid chromatography with light scattering detection. Optimization of parameters with a carbon dioxide/methanol mobile phase. Chromatographia, 33, 255-60. 

Nizery, D. Thiebaut, D. Caude, M. Rosset, R. Lafosse, M. Dreux, M. Improved evaporative Ught-scattering detection for supercritical fluid chromatography with carbon dioxide-methanol mobile phases. J. Chromatogr. 1989, 467,49-60. 

Shi, H. Strode, J.T.B., III Taylor, L.T. Fujinari, E.M. Chemiluminescence nitrogen detection for packed-column supercritical fluid chromatography with methanol modified carbon dioxide. J. Chromatogr. A, 1997, 757,183-191. 

Strode, J.T.B., IH Loughlin, T.P. Dowling, T.M. Bicker, G.R. Packed-column supercritical fluid chromatography with chemiluminescent nitrogen detection at high carbon dioxide flow rates. J. Chromatogr. Sci. 1998, 36,511-515. 

Bartman D, Schneider G M 1973 Experimental results and physiochemical aspects of supercritical fluid chromatography with carbon dioxide as the mobile phase. J Chromatogr 83 135-145... 

In supercritical fluid chromatography (SFC) the mobile phase is a supercritical fluid, such as carbon dioxide [15]. A supercritical fluid can be created either by heating a gas above its critical temperature or compressing a liquid above its critical pressure. Generally, an SFC system typically has chromatographic equipment similar to a HPLC, but uses GC columns. Both GC and LC detectors are used, thus allowing analysis of samples that cannot be vaporized for analysis by GC, yet cannot be detected with the usual LC detectors, to be both separated and detected using SFC. SFC is also in other... 

Von Bavel et al. [55] have developed a solid phase carbon trap (PX-21 active carbon) for the simultaneous determination of polychlorodibenzo-p-dioxins and polychlorodibenzofurans also polychlorobiphenyls and chlorinated insecticides in soils using superfluid extraction liquid chromatography for the final determination. Supercritical fluid extraction with carbon dioxide has been applied to the determination of dioxins in soil [114],... 

Steinheimer et al. [103] used supercritical fluid chromatography to extract Atrazine, diethyl Atrazine and Cyanazine from Canadian cornbelt soils by supercritical fluid extraction with carbon dioxide. 

The method based on immunosorbents coupled on-line with liquid chromatography-atmospheric pressure chemical ionization mass spectrometry [109], discussed in section 9.4.2.1, has been applied to the determination of substituted urea type herbicides. Supercritical fluid extraction with methanol modified carbon dioxide has been applied to the determinants of sulfonyl urea herbicides in soil [261],... 

A variety of modern instrumental analytical techniques have attracted considerable attention in the last decades as alternative separation and analysis methods with respect to HPLC. This includes, in particular, supercritical fluid chromatography (SFC), which utilizes condensed carbon dioxide (above or near its critical temperature of... 

More recently, some studies have reported the use of supercritical fluid chromatography (SEC) [479,480], Coupling SEC with SEE, sample extraction, preconcentration, and quantification can be performed in a single step. The mobile phase, carbon dioxide, can be modified by adding different... 

Supercritical-fluid chromatography has been applied by Ramsey et al. (213) for the determination of trimethoprim, along with three steroid hormones, in swine kidney. Separation was performed on a Spherisorb 5 amino-bonded column, using carbon dioxide with methanol modifier as the mobile phase. Detection at levels greater than 10 ppm was accomplished by tandem mass spectrometry using thermospray interface. However, this method lacks the sensitivity required to detect the low ppb levels likely to occur in milk and tissues. 

Supercritical fluid chromatography provides increased speed and resolution, relative to liquid chromatography, because of increased diffusion coefficients of solutes in supercritical fluids. (However, speed and resolution are slower than those of gas chromatography.) Unlike gases, supercritical fluids can dissolve nonvolatile solutes. When the pressure on the supercritical solution is released, the solvent turns to gas. leaving the solute in the gas phase for easy detection. Carbon dioxide is the supercritical fluid of choice for chromatography because it is compatible with flame ionization and ultraviolet detectors, it has a low critical temperature. and it is nontoxic. 

Supercritical fluid chromatography (SFC) has also been used in phospholipid analysis. According to Lafosse et al., phospholipid classes can be separated by SFC using a simple isocratic solvent consisting of 78.4/21.6 (w/w) mixture of carbon dioxide and a mixture of methanol, water, and triethylamine (95/4.95/0.05) in combination with a Zorbax Sil stationary phase detection was performed by evaporative light-scattering (20). 

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