Supercritical fluid chromatography/Fourier transform infrared spectrometry with an automatic diffuse reflectance interface

Shafer, Kenneth H.; Pentoney, Stephen L.; Griffiths, Peter R.

doi:10.1021/ac00292a015

Cited by 47 publications

(3 citation statements)

References 14 publications

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“…The first published works using both GC-like stationary phase based on the methyl(94)phenyl( 5)vinyl(1)polysiloxane [64,65] and octadecyl silica (C18) phase typical for the packed columns [66] were used for the separation of aliphatic hydrocarbons and polyaromatic hydrocarbons (PAHs). Consequently, pure silica particles were also used in 1986 to separate hydrocarbons [33] and pharmaceuticals [67]. With the development of the stationary phases for the packed columns, the same chemistries could also be used in packed capillary SFC with a little addition of the organic modifier (< 20 %) to the mobile phase [68].…”

Section: Packed Capillary Sfc Columnsmentioning

confidence: 99%

Columns in analytical‐scale supercritical fluid chromatography: From traditional to unconventional chemistries

Plachká

Pilařová

Horáček

et al. 2023

J of Separation Science

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Within this review, we thoroughly explored supercritical fluid chromatography (SFC) columns used across > 3000 papers published from the first study carried out under SFC conditions in 1962 to the end of 2022. We focused on the open tubular capillary, packed capillary, and packed columns, their chemistries, dimensions, and trends in used stationary phases with correlation to their specific interactions, advantages, drawbacks, used instrumentation, and application field. Since the 1990s, packed columns with liquid chromatography and SFC‐dedicated stationary phases for chiral and achiral separation are predominantly used. These stationary phases are based on silica support modified with a wide range of chemical moieties. Moreover, numerous unconventional stationary phases were evaluated, including porous graphitic carbon, titania, zirconia, alumina, liquid crystals, and ionic liquids. The applications of unconventional stationary phases are described in detail as they bring essential findings required for further development of the supercritical fluid chromatography technique.

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Section: Packed Capillary Sfc Columnsmentioning

confidence: 99%

Columns in analytical‐scale supercritical fluid chromatography: From traditional to unconventional chemistries

Plachká

Pilařová

Horáček

et al. 2023

J of Separation Science

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“…The residual pressure inside the column could be directly monitored by a manometer (6). A more rapid release of the pressure from inside the column could be achieved by carefully opening valve 3C which allowed additional slow release of the pressure through the tapered restrictor (9). After the pressure was completely released, the column was disconnected from the packing device and a second frit was created at the open I/ A, B, C, and D), (4) Tee connectors, (5) pressure transducer, (6) pressure display, (7) high pressure pump, (8) packing material reservoir, (9) capillary flow restrictor, (10) column, (1 1 ) sonicator, (12) bed supportfrit, (13) vacuum pump, and (14) pressure gauge.…”

Section: Materials and Equipmentmentioning

confidence: 99%

“…Packed capillary columns advantageously combine the positive characteristics of both column types [7]. These columns also possess relatively high sample capacities and low flow rates which make them suitable for direct interfacing with mass spectrometers (MS) [8] or Fourier transform infrared spectrometers (FTIR) [9].…”

Section: Introductionmentioning

confidence: 99%

Preparation of long packed capillary columns using carbon dioxide slurries

Malik

Lee

1993

J Microcolumn Separations

109

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Abstract. A new, reproducible method is described for the preparation of highly efficient fused silica packed capillary columns using pressure programmed liquid or supercritical carbon dioxide to carry the packing material into the capillary. The method allows facile preparation of long, uniformly packed capillary columns capable of producing over 240,000 theoretical plates in SFC. Columns of up to 10 meters in length were prepared using LC packing materials of different chemical nature and particle size. The new method does not require a separate step for preparing the slurry, and it is free from the drawbacks inherent in conventional slurry-packing methods. The lower viscosity and surface tension of carbon dioxide compared to conventional slurry-forming liquids, as well as the use of ultrasonic vibration and pressure programming in the packing process, provide favorable conditions for achieving packing uniformity over greater column lengths than is achievable by other packing techniques. Proper restrictors and appropriate decompression rates during the use of these columns in SFC were found to be very important in achieving optimum column performance. In comparison to the use of open tubular columns, higher efficiencies, greater sample capacities, and faster analysis speeds can be obtained. These advantageous features make the newly developed columns suitable for trace analysis, separation of very complex mixtures, and analysis of difficult-toseparate solutes.

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Supercritical fluid chromatography/Fourier transform infrared microspectrometry

Pentoney

Shafer

Griffiths

et al. 1986

J. High Resol. Chromatogr.

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SummaryThe feasibility of supercritical fluid chromatography/Fourier transform-infrared (SFC/FT-IR) microspectrometry is presented. In this approach to SFC/FT-IR, the chromatographic eluates are aspirated from the restrictor directly onto the surface of a moving window which then passes into the beam focus of an infrared microscope. Because the mobile phase is gaseous at ambient conditions, elimination of the mobile phase is easily accomplished. Detection limits in all interfaces between a chromatograph and an FT-IR spectrometer in which the mobile phase is eliminated are determined in large part by the area over which thesample is deposited. We have shown that SFCeluates can be condensed at ambient temperature into spots of 100 to 200pm in diameter. The microscope interface therefore serves to increase the sensitivity of the SFC/FT-IR measurements of these spots and detection limits in the low nanogram range are possible. Preliminary results obtained before any real attempts were made to optimize the deposition process indicate that identifiablespectra can beobtained in real timeat the50nglevel for chromatographic separations performed with a 100 pm i.d.wall coated open tubular column. Reproducible reconstructed chromatograms are obtained as each deposited eluate travels through the beam focus of the microscope. The concentration profile of deposited peaks was determined by IR measurements performed at 50 pm increments over the width of the peak to ascertain the deposition size. The results described in this paper, while not yet optimized, indicate the great potential of SFC/FT-IR microspectrometry.

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Supercritical fluid chromatography/Fourier transform infrared spectrometry with an automatic diffuse reflectance interface

Abstract: and by the U.S. Environmental Protection Agency under Cooperative Agreement CR812258-01 is gratefully acknowledged. S.L.P. wishes to thank the Shell Foundation for a Shell Analytical Fellowship while this work was being performed.

Cited by 47 publications

References 14 publications

Columns in analytical‐scale supercritical fluid chromatography: From traditional to unconventional chemistries

Columns in analytical‐scale supercritical fluid chromatography: From traditional to unconventional chemistries

Preparation of long packed capillary columns using carbon dioxide slurries

Supercritical fluid chromatography/Fourier transform infrared microspectrometry

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