Supercritical Fluid

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• Supercritical Fluid
• Extraction, Chromatography
• and Other Applications
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What is a Supercritical Fluid ?

• When the pressure and temperature of a substance
  is raised above its critical pressure and
  critical temperature (the critical point) the
  substance enters the supercritical state.
• A Supercritical Fluid is a substance with both
  gas- and liquid-like properties.

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Critical Temperature and Pressure

• The Critical Temperature (Tc) is the maximum
  temperature at which a gas can be converted to a
  liquid by increasing the pressure.
• The Critical Pressure (Pc) is the maximum
  pressure at which a liquid can be converted to a
  gas by increasing the temperature.

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Phase Diagram of Carbon Dioxide
Gas
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Physical Properties of CO2
Phase Gas SCF Liquid
Density 0.62.0 x 10-3 0.2 0.9 0.8 1.0
viscosity 0.53.5 x 10-4 2.09.9 x 10-4 0.32.4 x 10-2
Diffusivity 0.01 1.0 0.53.3 x 10-4 0.52.0 x 10-5
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Advantages of Supercritical Fluids as solvents

• Solvating power related to density (at constant
  T)
• Gas-like mass transport properties
• Facile penetration into porous material

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Critical Parameters of Common Fluids
Source SFE and Its use in Chromatographic
Sample Preparation Ed. S. Westwood. Chapter 1
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Advantages of CO2 for SFE

• Low critical parameters
• Inert, Non-toxic, Nonflammable, Non-corrosive
• Easily purified (inexpensive)
• Nonpolar dielectric constant similar to hexane
• Modifiers can be used to increase polarity

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Supercritical Fluid Extraction (SFE)

• Basic Theory

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SFE System Components
Liquid Carbon Dioxide (requires a dip tube)
Restrictor
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Advantages of SFE over Solvent Extraction

• Faster
• Results in minutes rather than hours
• Selectivity results in cleaner extracts
• Low Critical Parameters
• Handling of thermally labile analytes
• Non-hazardous solvents
• Automated
• Cost per test is lower
• Limited or no solvent removal required
• No solvent disposal costs

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The Mechanism of SFE

• A Three Step Process
• Dissolving/Resolving analyte(s)
• 2. Sweeping the analyte(s) from the matrix
• 3. Trapping the analyte(s)

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SFE Mechanism
SC-CO2 diffuses matrix, dissolves and
resolves analyte from the matrix
SC-CO2 dissolved analyte to the trap
High Pressure Liquid CO2
Heat
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Trapping
Gaseous CO2
Gaseous CO2

• Trapping Solid
• High Surface Area
• Adequate Amount
• Trapping Liquid
• High Surface Tension
• Analyte is Soluble
• Low Volatility
• Pressurized
• Cryogenically Cooled

• CO2 is changing
• from a SF (2 ml/min)
• to an expanded gas
• (1 L/min)
• Analyte no longer
• soluble
• Mechanical movement
• of analyte due to the
• rapid expansion requires
• the use of trapping
• material

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SFE - Method Development

• Pressure
• Increase pressure increases density increase in
  solubilizing power.
• Temperature
• Increase temperature may decreases density
  decrease in solubilizing power (ie CO2 at 100
  bar)
• Extraction Time
• Flow Rate
• Fluid Composition
• Co-solvents/modifiers
• Reactant Additive
• Static vs. Dynamic Extraction

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Why Use Modifiers?Analytes that have polar
components require the use of a co-solvent
Triglycerides
Phospholipids
CH2OCOR1 R2COOCH
CH2OCOR3
CH2OCOR1 R2COOCH O
CH2OPOR3 O-
R 1 2 groups are long chain hydrocarbons
(nonpolar), while R 3 contains phosphorus and
nitrogen and is polar
R 1, 2 3 groups are long chain hydrocarbons
(nonpolar)
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Modifiers (Co-solvents) in SFE

• Role of Modifiers in SFE
• Changes in Solvent Polarity
• Interaction with Matrix
• Interaction with Analyte
• Methods of Addition
• Directly into extraction cell (spiking)
• On line modifier addition (uses a second pump)

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SFE vs. Traditional Sample Extraction Methods

• Conclusion
• SFE can be versatile, selective and faster
• SFE reduces hazardous solvent use and cost
• SFE can produce cleaner, more concentrated
  extracts for post extraction analysis

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Analysts Time Allotment
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Routine and Novel Applications of Analytical SFE
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SFE for Research
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Environmental SFE Applications

• Matrices
• Soil
• Tissue
• Clay
• Sandy Loam
• Sludge
• River Sediment
• Marine Sediment
• Fly Ash
• Incinerator Ash

• Target Analytes
• TPH
• PAH
• PCBs
• Pesticides
• Dibenzofurans
• Dioxins

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Approved Methods Environmental

• US EPA 3560 - TPH in Soil Supercritical Fluid
  Extraction of Total Recoverable Petroleum
  Hydrocarbons
• US EPA 3561 - PAH in Soil Supercritical Fluid
  Extraction of Polyaromatic Hydrocarbons
• US EPA 3562 - PCB and OCP Supercritical Fluid
  Extraction of Polychlorinated Biphenyls (PCBs)
  and Organochlorine
• US EPA 3545 Pressurized Fluid Extraction (PFE)
• USDOE STD-3013-99 Determination of Residual
  Water in Impure Plutonium Oxides
• AOAC draft SFE-GC/MS determination of pesticide
  residues in non-fatty fruits and vegetables

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Pharmaceutical/Natural Product Applications
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SFE of Natural Products -- Roger M. Smith LC-GC
International, Jan. 1996, 9-15
Catharanthus roseus German chamomile Magnolia grandiflora Tansy
Chamomile flowerheads Ginger Peppermint Thyme
Clove Oil Kola nuts Pimento Turmeric
Dragon head Lavender Poppy seeds Wheat germ oil
English yew Lemon grass Rosemary
Feverfew Lemon peel Savory
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Microbial Natural ProductsR. M. Smith, op. cit.
Organism Extract
Agaricus species Carboxylic and fatty acids
Beuveria nivea Cyclosporin
Filamentous fungi Polyunsaturated fatty acids
Flour, moldy bread, mushrooms Ergosterol
Moldy bran Sterol
Moldy grain Aflatoxin
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Extracts from BiomassR. M. Smith, op. cit.
Microorganism Extract
Actinomycete species Mycolutein and luteoreticulin
Actinomycete species Oligomycin A
Aspergillus fumigatus Sydowinin B and epoxide
Bipolaris urochloae Ophiobolin A
Penicillium expansum Chaetoglobosin A
Penicillium sclerotium ()-Sclerotiorin
Streptomyces species Elaiophylin
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Summary R. M. Smith, op. cit.

• Extracts typically cleaner than those obtained
  with organic solvents.
• Mild conditions minimize degradation.
• SFE methods are faster than organic solvent
  extractions.

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Extraction of Pharmaceuticals Using Pressurized
Carbon DioxideJ. R. Dean, S. Khundker, J. Pharm.
Biomed. Anal, 15 (1997) 875-886

• Recoveries from 81 - 95
• CO2 and CO2 with modifiers
• Generally faster than other methods with better
  selectivity for target analytes.
• Preconcentration steps could be eliminated in
  some cases.
• Liquid matrices required immobilization on solid
  support or SPE cartridge.

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Animal Feeds J. R. Dean, S. Khundker, op. cit.
Analyte Matrix
Menadione Rat chow
Tipradane Rodent diet
Hypolipidermic drug Rat feed
Halogenated aromatic phenoxy derivatives Dog feed/rodent feed
Atovaquone Rat feed
Fluconazole Animal feed
Propanolol, Tamoxifen, ZM 95527, 169369 Rodent diet
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FormulationsJ. R. Dean, S. Khundker, op. cit.
Analyte Matrix
Megesterol Acetate Tablet
Felodipine Tablet
Benzodiazipines (7) Tablet/capsule
Caffeine,vanillin Tablet
Vitamin A, E Tablet
Retinol palmitate, tocopherol acetate Ointment
Polymyxin B sulphate Cream/Ointment
Acylvoir Ointment
Sulfamethazole, trimethoprim Septra infusion
Triamincinolone Dermatological patches
Misoprostol Hydroxypropyl methylcellulose
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Biological MatricesJ. R. Dean, S. Khundker, op.
cit.
Analyte Matrix
Veterinary drugs (4) Pig kidney
Nitrobenzamide residue Liver
Codeine, morphine, ethyl morphine Hair
Ketorolac, flavone Plasma
Mebervine alcohol Dog plasma
Morphine Serum
Beudesonide Plasma
Caffeine Kola nuts
Taxanes Yew tree needles
Chinese herbal medicines Plants
Diosgenin Tubers of Dioscorea nipponica
Taxol and baccatin III Needles of Taxus cuspidata
Zingiber zerumet rhizomes Plants
Mevinolin and hydroxy acid form Fermentation broth
Phylloquinone Soy protein and infant formula
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MiscellaneousJ. R. Dean, S. Khundker, op. cit.
Analyte Matrix
Triprolidine, pseudoephedrine Aqueous
Steroids (10) Aqueous
Ibuprofen Aqueous
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Natural Materials StudiedM. J. Noh, et. al., op.
cit.
Specific Name Part Used
Lycium chinese Fruit
Schizandre chinensis Fruit
Citrus unshiu Fruit bark
Angelica gigas Root
Cornus officinalis Fruit
Cnidium officinale Rhizome
Ginko biloba Leaf
Aralia cordata Root
Evodia officinalis Fruit
Crataegus pinnatifida Fruit
Paeonia lactiflora Root
Leonurus sibricus All
Sophora japonica Flower
Artemisia capillaris All
Platago asiatica Seed
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Natural Materials Studied, contd.M. J. Noh, et.
al., op. cit.
Specific Name Part Used
Ephedra sinica All
Aconitum carmichaeli Tuber
Scolopendra subspines All
Paeonia suffruticosa Root
Pueraria thunbergiana Root
Polygala tenuifolia Root
Coptis japonica Rhizome
Astragalus membranaceus Root
Eucommia ulmoides Stem bark
Bupeuri falcatum Root
Acanthopanax sessiliflorum Bark
Epimedium koreaum All
Morus alba Root bark
Artium lappa Fruit
Spirodela polyrhiza All
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Summary M. J. Noh, et. al., op. cit

• For many materials, SFE yielded extracts with
  higher bioactivity than LSE.
• SFE was found to be more selective than LSE for
  target compounds.
• SFE conditions could be optimized to produce
  maximum levels of bioactivity.

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Drug Residues
Analyte Matrix Reference
Sulfamethazine Swine Muscle Tissue Cross, et.al.
Anabolic Steriods Bovine Tissue (Muscle and Liver) Houpalahti and Henion
Opiates Hair, blood and tissue Multiple Authors
Temazepam Whole Blood Scott and Oliver
Cocaine, benzoylecgonine, codeine and morphine Hair Brewer, et.al.
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Study Summary

• Compared to a conventional SPE method, the SFE
  method was more efficient and gave cleaner
  extracts with recoveries above 80
• K.S. Scott, J.S. Oliver, J. Anal.Toxicol. 21
  (1997) 297.

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Supercritical Fluid Chromatography

• SFC is a separation technique similar to HPLC and
  GC where the mobile phase or carrier gas is
  replaced by a supercritical fluid

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Limitations of GC and HPLC

• GC Sample Limitations
• Volatility
• Thermal stability
• Low molecular weight
• HPLC Analytical Limitations
• No universal detector
• Low efficiency
• Low resolution

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SFC Overcomes Limitations of GC and HPLC

• Extends molecular weight range of GC
• Lower operating temperature than GC
• Faster separation time than HPLC
• Higher separation efficiency than HPLC
• Universal detector can be used, FID
• Both packed (HPLC-type) and GC-type columns can
  be used

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Carbon Dioxide, CO2has desirable properties as a
SFC solvent

• Inexpensive
• Highly pure
• Very low UV absorbance
• NO FID background noise
• Low critical pressure and temperature
• Non-toxic
• Supercritical CO2 behaves as a nonpolar solvent
  such as heptane
• Polar organic modifiers can be mixed with CO2 for
  more polar samples

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SFC Applications

• Industrial
• Synthetic oligomers, polymers / additives
• Surfactants (polyglycols)
• Oligo / polysaccharides, sucrose polyesters
• Pesticides
• Isocyanates
• Dyes
• Waxes

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SFC Applications

• Biochemical
• Steroids
• Prostaglandins
• Fatty acids / lipids
• Antibiotics
• Drugs of abuse

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SFC Applications

• Fossil Fuels
• Fractionation of petroleum and coal-derived
• fluids
• Hydrocarbon group analysis
• Simulated distillation

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Other Applications of
Supercritical Fluid

• Supercritical Fluid Cleaning
• Supercritical Fluid Drying
• Supercritical Fluid Reactions
• Micro Particles Formation
• Supercritical Water Oxidation System
• Others

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Applications of Supercritical Fluid Technologies
in Taiwan

• IN THE PAST

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Applications of Supercritical Fluid Technologies
in Taiwan

• AT PRESENT

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Applications of Supercritical Fluid Technologies
in Taiwan

• IN THE FUTURE

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Thanks For Your Attention !

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