Thermal extraction

FoodApphca.tlons, Carbon dioxide, a nontoxic material, can be used to extract thermally labde food components at near-ambient temperatures. The food product is thus not contaminated with residual solvent, as is potentially the case when usiag coaveatioaal Hquid solveats such as methylene chloride or hexane. In the food iadustry, CO2 is not recorded as a foreign substance or additive. Supercritical solvents not only can remove oils, caffeiae, or cholesterol from food substrates, but can also be used to fractionate mixtures such as glycerides and vegetable oils iato aumerous compoaeats. 

J. J. Vreuls, G. J. de Jong, U. A. Th Brinkman, K. Grob and A. Artho, On-line solid phase extraction-thermal desorption for- introduction of large volumes of aqueous samples into a gas cliromatograph , 7. High Resolut. Chromatogr. 14 455-459 (1991). 

Tienpont, B., David, F., Desmet, K. and Sandra, P. (2002) Stir bar sorptive extraction-Thermal desorption-capillary GC-MS applied to biological fluids. Anal. Bioanal. Chem. 373, 46-55. 

Of the above-mentioned challenges of oil-sands production, the heavy dependence on natural gas is among the most critical. Table 3.5 shows the specific natural gas demand per barrel of bitumen for mining and extraction, (thermal) in-situ recovery and upgrading operations, as well as for the production of hydrogen. Depending on the recovery process, up to 25% of the energy content of the SCO is used in the form of natural gas. 

Huang, C., Liang. H. Shouting, H. (1996) Determination of organic compounds in wastewater by gas extraction/thermal desorption/gas chromatography-mass spectrometry. Sepu, 14, 421-424 (in Chinese) [Chem. Abstr. 126, 094416]... 

Solid Phase Extraction Thermal Conductivity Detector Ultraviolet (Spectrophotometry)... 

Ochiai, N., K. Sasamoto, H. Kanda, and S. Nakamura. 2006. Fast screening of pesticide multiresidues in aqueous samples by dual stir bar sorptive extraction-thermal desorption-low thermal mass gas chroma-tography-mass spectrometry. J. Chromatogr. A 1130 83-90. 

Llorca-Porcel, J., G. Martinez-Sanchez, B. Alvarez, M.A. Cobollo, and I. Valor. 2006. Analysis of nine polybrominated diphenyl ethers in water samples by means of stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry. Anal. Chim. Acta 569 113-118. 

R.M. Black, R.J. Clarke, D.B. Cooper, R.W. Read and D. Utley, Application of headspace analysis, solvent extraction, thermal desorption and gas chromatography-mass spectrometry to the analysis of chemical warfare samples containing sulfur mustard and related compounds, J. Chromatogr., 637, 71-80 (1993). 

Within the extracts (thermal or enzymatic), besides polysaccharides, mannoproteins were proven to be the main components, the molecular characterization of which has been carried out using SEC and SDS-PAGE (Martfnez-Rodrfguez et al. 2007 Nunez et al. 2006). Results showed in both cell wall extracts a protein band corresponding to a relative molecular mass of 30kDa (Eig. 5.9). Moreover, three bands, which were absent from the extract obtained enzymatically, with relative molecular masses between lOkDa and 21.5 kDa were observed in the thermal extract. Only glycoproteins with Mr between 10 kDa and 21.5 kDa, were proven to be foam-active though the protein at 30 kDa (also present in the enzymatic extract) was found to be inactive. 

Prieto, A., Zuloaga, O., Usobiaga, A., Etxebarria, N., Fernandez, L.A., Marcic, C., de Diego, A. Simultaneous speciation of methylmercury and butyltin species in environmental samples by headspace-stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry. J. Chromatogr. A 1185, 130-138 (2008)... 

Bonet-Domingo, E., Grau-Gonzalez, S., Martin-Biosca, Y., Medina-Hemandez, M.J., Sagrado, S. Harmonized internal quality aspects of a multi-residue method for determination of forty-six semivolatile compounds in water by stir-bar-sorptive extraction-thermal desorption gas chromatography-mass spectrometry. Anal. Bioanal. Chem. 387, 2537-2545 (2007)... 

Removal of extractables from an elastomer or plastic matrix can be accomplished by a variety of techniques, including solvent extraction (e.g., reflux and Soxhlet), supercritical fluid extraction, thermal evolution, etc. Jenke has thoroughly discussed and classified extraction strategies for container closure system components associated with a drug product leachables assessment. His discussion is based on two so-called directives paraphrased as follows ... 

Stir bar sorptive extraction Gas-phase extraction Thermal desorption... 

Fig. 8. Fused NUV/IALFS image of lidar optical thickness overlaid with extracted thermal and ultraviolet features (all data rectified)...

The thermal desorption must take place at a temperature below the decomposition point of other materials in the sample matrix. Solid materials should have a high surface area (e.g., powders, granules, flbers). Bulk materials are ground with a coolant such as solid carbon dioxide prior to weighing. This technique simplifies sample preparation and avoids the necessity of dissolving samples or solvent extraction. Thermal desorption is well suited for dry or homogeneous samples such as polymers, waxes, powders, pharmaceutical preparations, solid foods, cosmetics, ointments, and creams. There is essentially no sample preparation required. 

Leon, V. M., Alvarez, B., Cobollo, M. A., Munoz, S., and Valor, I., Analysis of 35 priority semivolatile compounds in water by stir-bar sorptive extraction-thermal desorption-gas chromato-graphy-mass spectrometry I. Method optimisation, J. Chromatogr. A, 999, 91-101, 2003. 

Baltussen, E., David, F., Sandra, P., Janssen, H.-G., and Cramers, C. A., Retention model for sorptive extraction-thermal desorption of aqueous samples application to the automated analysis of pesticides and polyaromatic hydrocarbons in water samples, J. Chromatogr. A, 805, 237-247, 1998. 

Sandra, P., Tienpont, B., and David, F., Multi-residue screening of pesticides in vegetables, fruits and baby food by stir bar sorptive extraction-thermal desorption-capiUary gas chromatography-mass spectrometry, J. Chromatogr. A, 1000, 299-309, 2003. 

Louter, A. J. H., Van Doornmalen, J., Vreuls, J. J., and Brinkmann, U. A. Th., Online solid phase extraction-thermal desorption-gas chromatography with ion trap detection tandem MS for the analysis of microcontaminants in water, J. High Res. Chromatogr., 19, 679-685, 1996. 

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