Packed column supercritical fluid chromatography of polysiloxanes using pure and hexane modified carbon dioxide with flame ionization and ultraviolet detection

Berger, Terry A.; Todd, B. S.

doi:10.1007/bf02492497

Cited by 8 publications

(5 citation statements)

References 20 publications

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“…A methyl silicone stationary phase was found to be much less retentive for ethoxylates and proproxylates than the C8 and C18 phases used to separate silicone oils [21], and was also less retentive than a C4 column. Higher temperatures tended to be more effective in eluting the heavier ends of the samples, even though the maximum density at the highest available pressure was reduced.…”

Section: Resultsmentioning

confidence: 99%

Packed column supercritical fluid chromatography of oligoethers using pure carbon dioxide with flame ionization and ultraviolet detection

Berger¹,

Todd²

2001

Chromatographia

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SummaryTMS derivatives of ethoxyJates ancl proproxyJates were separated with high resolution, on standard bore ancl 2 mm packed columns, using both UVancl FID cletection.A methyl silicone column was found to dramatically decrease retention ancl allow the elution of heavier ohgomers, compared to C18 or C8. Standard bore columns eliminated pre-column splits, ancl allowed full loop injections. Reproducibility for individual homologs was fou ncl to be 0.2 -0.3% in retention time ancl 0.85 to 1.3% in area, over 10 consecutive automated injections.The UV clara was fou ncl to be equivalent to "corrected" FID data. Switching to the UV detector at 191 nm, eliminated any neecl for a fixed restrictor. Slow ancl fast program rates were shown to provide equivalent mass distribution information.

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Section: Resultsmentioning

confidence: 99%

Packed column supercritical fluid chromatography of oligoethers using pure carbon dioxide with flame ionization and ultraviolet detection

Berger¹,

Todd²

2001

Chromatographia

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“…Two chromatograms of a silicone oil [16], detected using both the FID and UV UV Time Figure 3. UV and FID chromatograms of DC-200 Dimethylsiloxane with a viscosity of 10 centistokes collected using a Hypersil ODS column, at 150 ~ Pure carbon dioxide was pumped at 2ml.min 1.…”

Section: Resultsmentioning

confidence: 99%

Simple correction for variable post column split ratios using pure carbon dioxide in packed column supercritical fluid chromatography with independent pressure and flow control

Berger¹

2001

Chromatographia

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Packed column supercritical fluid chromatographs (SFC) with independent control of pressure and flow produce constant efficiency but suffer from variable response factors when using a post column split into a mass sensitive detector. Most of the flow passes through a backpressure regulator, but a small fraction of the flow passes through a fixed restrictor in the base of a detector like the FID. Since the flow through a fixed restrictor increases with pressure, a changing split ratio into the detector and non-linear response results. For samples requiring a pressure program to elute both light and heavy components, distorted mass distribution measurements result.A simple correction for this variable response is presented. Restrictor flow is a linear function of pressure. Division of the FID detector signal by the current pressure corrects for variations in post column split ratios. The correction only works for constant mass flow pumps and does not work for mixed fluids, syringe pumps or reciprocating pumps with inadequate compressibilily compensation.

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“…SFC has long been used for the characterization of polysiloxanes. In the work of Berger and Todd, the molecular weight range of SFC was extended beyond the reach of pure CO 2 (estimated at 25 000 for pure CO 2 ) by the addition of hexane as a mobilephase modifier (92). Detection was by ultraviolet absorbance at 191 nm.…”

Section: Applicationsmentioning

confidence: 99%

Supercritical Fluid and Unified Chromatography

Chester

Pinkston

2004

Anal. Chem.

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Review ContentsTheory and Fundamental Measurements 4606 Mobile Phases and (Achiral) Stationary Phases 4607 Instrumentation, Techniques, and Performance 4609 Preparative Separations 4609 Detection 4609 Applications 4610 Food-Related Applications 4610 Natural Products 4610 Fossil Fuels 4610 Synthetic Oligomers, Polymers, and Polymer Additives 4610 Achiral Pharmaceuticals and Bioactive Compounds 4611 Chiral Applications 4611 Literature Cited 4612Supercritical fluid chromatography (SFC) and related unified chromatography techniques using compressible, solvating fluids and conventional liquids at high or ultrahigh temperatures continue to grow in use. However, continuing the trend in recent years, there has been a further decrease in fundamental work and in the number of published research articles.Despite this, interest among end users continues to grow, particularly in pharmaceutical applications. Pharmaceutical researchers also continue to lead in publishing applications, perhaps reflecting the higher importance placed on publication in this business than in most others.During this review period, one analytical instrument supplier (for whom SFC was a minor product area) left the business, but another supplier, one fully dedicated to this field, enthusiastically joined. Growth also continues in the preparative SFC area and in materials processing using supercritical and related fluids, and this is expected to continue stimulating analytical applications.As in the past, we have made a very loose interpretation of the term "supercritical" for the purposes of selecting articles to cite (and in keeping with the underlying unified chromatography theme) and have included any solvating fluid that is used in either condensed or supercritical form at a temperature above its normal vaporization temperature or above the usual temperature range of conventional HPLC. We resume from our last report (1) and have examined the literature abstracted in the ISI Current Contents Connect (http://isicc.com/CCC.cgi) database through November, 2003. We found about 200 articles from which we have cited a fraction, representative of recent progress. THEORY AND FUNDAMENTAL MEASUREMENTSSeveral general reviews appeared that may be useful to people new to the field (2-4). Dominguez et al. presented a revision of the 1993 IUPAC Nomenclature for Chromatography that addresses hold-up volume and the physical meaning of several terms (5). The measurement and meaning of hold-up times and volumes as well as derived parameters, such as solute retention factor in an SFC instrument or other chromatographic system in which the mobile phase is compressible, solvent strength changes with mobile-phase density, and pressure and temperature change longitudinally along the column, will require some additional attention.Amines have been successfully determined by SFC techniques for years, but there has been uncertainty if or when amines react with CO 2 , if the peaks actually migrating through a column under SFC conditions are the original amines or something els...

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Packed column supercritical fluid chromatography of polysiloxanes using pure and hexane modified carbon dioxide with flame ionization and ultraviolet detection

Cited by 8 publications

References 20 publications

Packed column supercritical fluid chromatography of oligoethers using pure carbon dioxide with flame ionization and ultraviolet detection

Packed column supercritical fluid chromatography of oligoethers using pure carbon dioxide with flame ionization and ultraviolet detection

Simple correction for variable post column split ratios using pure carbon dioxide in packed column supercritical fluid chromatography with independent pressure and flow control

Supercritical Fluid and Unified Chromatography

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