Investigation of retention and selectivity in high‐temperature, high‐pressure, open‐tubular supercritical fluid chromatography with CO<sub>2</sub> mobile phase

Chester, T. L.; Innis, D. P.

doi:10.1002/mcs.1220050508

Cited by 8 publications

(7 citation statements)

References 6 publications

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“…This may be attributed to a decrease of polar interaction, such as hydrogen bonding. 15,16 A similar behavior was observed in the P-NP system without using a coupling restrictor, as discussed above (Fig. 2), and all of the NP-P systems using a coupling restrictor (Fig.…”

Section: Temperature Effectsupporting

confidence: 81%

Serially Coupled Capillary Columns Supercritical Fluid Chromatography with a Coupling Restrictor

2003

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Section: Temperature Effectsupporting

confidence: 81%

Serially Coupled Capillary Columns Supercritical Fluid Chromatography with a Coupling Restrictor

2003

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“…The percentage of triepoxy TG (54.4%) we obtained is slightly higher than that measured by HPLC (18,24) and than that predicted theoretically with use of a random distribution: 41.9%, based on the oil. Similar SFC calibration curves also have been displayed elsewhere (5,28,29). The slope of the calibration curve is initially steep; then it gradually decreases.…”

Section: Tn2 a J~ts4supporting

confidence: 71%

“…The low-MW analytes, in fact, were poorly resolved from the solvent peak. These trends with respect to column temperature were exhibited during analysis of high-MW TG of vernonia, crambe, and meadowfoam oils (see above) and for surfactant analysis with a similar nonpolar stationary phase (28). When elution density replaces retention time as the ordinate, two separate but nearly parallel curves result, with the curve for the analysis at 200~ being below the 100~ curve (Fig.…”

Section: Tn2 a J~ts4mentioning

confidence: 68%

Supercritical fluid chromatographic analysis of new crop seed oils and their reactions

Hayes

Kleiman

1996

J Americ Oil Chem Soc

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Supercritica/fluid chromatography (SFC) with an open tubular column of nonpolar stationary phase separated triglycerides from crambe, meadowfoam, Euphorbia lagascae, and vernonia oils based on their molecular weight. The triglyceride compositions were consistent with the literature. SFC proved also to be a valuable tool in analyzing lipase-catalyzed transesterification reactions where lesquerella oil and estolides were among the substrates employed. Analyte molecular weights could be estimated from a retention time-(or elution density-) molecular weight calibration curve. An increase in isothermal column temperature during SFC pressure or density programming improved the resolution of high-molecular-weight (>600 Da) analytes but yielded poorer resolution for analytes of molecular weight < 200. A simultaneous pressure and temperature ramping program proved superior in enhancing resolution in several instances.Supercritical fluid chromatography (SFC) is becoming a valuable tool in the analysis of lipids as it is replacing high-performance liquid chromatography (HPLC) and gas chromatography (GC) as the analytical tool of choice for several applications. SFC can be considered a hybrid of GC and HPLC because supercritical fluids possess properties (e.g., density, viscosity, and self-diffusion coefficient) intermediate between gases and liquids. For example, separation of analytes by relative volatility, as encountered in GC, can also be achieved with SFC but at much lower elution temperatures and without derivatization. The use of lower temperatures protects analytes that are susceptible to thermal degradation, such as polyunsaturated and oxygenated lipids. With the onset of equipment that allows addition of modifiers to the supercritical fluid mobile phase, HPLC-Iike separations can be achieved by SFC, but a larger range of detectors--GC-style

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“…The tra n s fer line may play a role of fo c u s i n g solutes on the secondary column to some extent. In addition to pressure, temperature also affected the selectivities as in single column SFC [6][7][8]. Thus, two-dimensional SFC with the present interface can offer versatile methods for analyzing complex mixtures and cl o s e ly re l ated compounds.…”

Section: Comparison Of Elution Methods and Effects Of Resistance Of Tmentioning

confidence: 87%

A simple flow switching interface for two-dimensional capillary supercritical fluid chromatography

Hishimoto¹,

Hirata²

1998

Analusis

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Supercritical fluid chromatography (SFC) has been recog n i zed as a powerful sep a ration technique supplementing gas (GC) and liquid chromatography (LC). Although capillary SFC has a high resolving power, the efficiency of a single capillary column is still inadequate for the separation of closely related compounds and complex mixtures such as isomeric compounds and environmental and biological samples. Multi-dimensional chromatography is an excellent technique for obtaining increased resolving power. Although various forms of multi-dimensional (mostly twodimensional) chromatography using GC, LC and SFC have been rep o rted and some of them are well established as reviewed [1,2], a limited number of reports have been published with respect to capillary SFC-SFC [3,4].In this study, we developed a simple flow switching interface for two-dimensional capillary SFC. A novel plumbing method to construct the system was also developed. The primary column was a non-polar methyl polysiloxane column and the secondary column a polar polyethylene glycol column. This geometry was more effective for controlling the resolutions on the secondary column than the reversed one. Pressure and temperature affected the selectivity on the secondary column as in single column SFC. Experimental ChemicalsA mixture of para ffins (C 1 8 -C 2 6 ) , fatty acid methyl esters (C 16 Me-C 22 Me) and alcohols (C 12 OH-C 18 OH) (Tokyo Kasei, Tokyo, Japan) with even carbon atoms was used for fundamental study on two-dimensional SFC as a test sample. C h o l e s t e rol (chol) and its fatty acid derivat ive s , l a u rat e ( ch o l -1 2 : 0 ) , my ri s t ate (ch o l -1 4 : 0 ) , p a l m i t ate (ch o l -1 6 : 0 ) , palmitoleate (chol-16:1), stearate (chol-18:0), oleate (chol-1 8 : 1 ) , l i n o l e ate (ch o l -1 8 : 2 ) , l i n o l e n ate (chol-18:3) and a ra ch i d o n ate (ch o l -2 0 : 4 ) , we re purchased from Sigma ( S t . L o u i s , M O, USA). Oligo m e ric sample with two b ra n ches of polyox ye t hylene (2,4,7,9-tetra m e t hy l -4 , 7 -bis(polyoxyethylene)-5-decyne) was obtained from Hayashi Kasei (Nagoya, Japan). All these samples were dissolved in dichloromethane. Ultra high purity carbon dioxide (ShowaTansan, Yokkaichi, Japan) was used as mobile phase. InstrumentsThe pump was an LC-6A liquid ch ro m at ograph pump ( S h i m a d z u , Kyo t o , Japan) equipped with a pump head cooler (MC-28T, Netsudenshi Kogyo, Tokyo, Japan) and a home-made pre s s u re progra m m e r. The superc ritical fl u i d ch ro m at ograph was a HP 5840A gas ch ro m at ograp h (Hewlett-Packard, Avondale, Penn., USA) with dual flame ionization detectors (FID). The FID temperature was held at 300 or 350 o C. Capillary columns were HP-1 (100 µm i.d. × 10 m, 0.40 µm film thickness) and HP-WAX (100 µm i.d. × 10 m, 0.20 µm film thickness). In most cases, the former was used as a primary column and the latter as a secondary column in two-dimensional SFC. The column temperature was between 80 and 120 o C. Samples were injected with a Rheodyne 7520 injector (Cotati, C...

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Investigation of retention and selectivity in high‐temperature, high‐pressure, open‐tubular supercritical fluid chromatography with CO₂ mobile phase

Cited by 8 publications

References 6 publications

Serially Coupled Capillary Columns Supercritical Fluid Chromatography with a Coupling Restrictor

Serially Coupled Capillary Columns Supercritical Fluid Chromatography with a Coupling Restrictor

Supercritical fluid chromatographic analysis of new crop seed oils and their reactions

A simple flow switching interface for two-dimensional capillary supercritical fluid chromatography

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Investigation of retention and selectivity in high‐temperature, high‐pressure, open‐tubular supercritical fluid chromatography with CO2 mobile phase

Cited by 8 publications

References 6 publications

Serially Coupled Capillary Columns Supercritical Fluid Chromatography with a Coupling Restrictor

Serially Coupled Capillary Columns Supercritical Fluid Chromatography with a Coupling Restrictor

Supercritical fluid chromatographic analysis of new crop seed oils and their reactions

A simple flow switching interface for two-dimensional capillary supercritical fluid chromatography

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Product

Resources

About

Investigation of retention and selectivity in high‐temperature, high‐pressure, open‐tubular supercritical fluid chromatography with CO₂ mobile phase