Water extraction method

CO2 extraction has been prevalent for the isolation of essential oils and other natural lipophilic pigments like carotenoids. Hot water and superheated water extraction methods are used for analytical preparation of polar pigments. The technique is commonly referred to as subcritical water extraction because the practitioners of this approach come from SEE backgrounds. 

Samples containing heavy oil, along with the volatile components can severely contaminate pnrge-and-trap instrumentation, and caution is advised when interpreting the data. For such samples it may be advisable to use a separatory funnel for the water extraction method for semivolatiles (EPA 3520). In this method, the sample is ponred into a funnel-shaped piece of glassware, solvent is added, and the mixtnre is shaken vigorously. After layer separation, the extract (i.e., the solvent layer) is removed. Altered, dried with a desiccant, and concentrated. Multiple extractions on the same sample may increase overall recovery. 

Another commonly nsed water extraction method for semivolatiles involves continuous liquid-liquid extraction (EPA 3520). In this method, the sample... 

Because LPS molecules in different bacteria have different structures and amphi-pathic properties, there is no universal method for extraction of LPS. Several methods have been developed each favors some specific groups of LPS. For example, the phenol-water extraction method favors S-LPS extraction, but not R-LPS (Hickman and Ashwell, 1966 Kasai and Nowotny, 1967) the ether extraction method favors the extraction of R-LPS (Galanos et al., 1969). Both methods for large scale or micro-scale extractions have been developed. Agents used by different extraction methods are listed in Table 2.1. 

One major limitation of the phenol-water extraction method is that R-LPS frequently partitions into the phenol phase (Hickman and Ashwell, 1966 Kasai and... 

Di Bonito, M., Breward, N., Crout, N., Smith, B., and Young, S. (2008). Soil pore water extraction methods for trace metals determination in contaminated soils. In Environmental Geochemistry Site Characterization, Data Analysis, and Case Histories (B. De Vivo, H. E. Belkin, and A. Lima, eds.). Elsevier Science Publishers, Amsterdam, The Netherlands. 

Overview of Selected Soil Pore Water Extraction Methods for the Determination of Potentially Toxic Elements in Contaminated Soils Operational and Technical Aspects... 

Overview of Selected Soil Pore Water Extraction Methods... 

Measurement of surface pH sometimes yields values close to those obtained by the water extraction methods, but frequently rather large differences are observed. Interpretation of test results must be qualified because the pH may not be uniform throughout the thickness of the sheet particularly in coated papers, significant differences have been observed between the pH of the coating and that of the base stock. 

Consequently, since the calculations described above did not consider the energy to keep the temperature at 100 C during the extraction time (2 x 0.5 hours), the conventional extraction method requires at least six times the amount of energy required for the extraction with hot compressed water at 140 C with no time at temperature. At the same time, the conventional extraction method emits at least six times the amount of CO than does the hot compressed water extraction method. 

Method 14 - Preparation of water extract Method 15 - Tear strength Method 16 - Air flow value... 

These changes result in LPS and LOS preparations that have less contamination with nucleic acids and produce somewhat greater yields. One major limitation of the phenol-water extraction method is that LPS with truncated polysaccharide components or the more hydrophobic, shorter chain LOSs frequently partition into the phenol phase, as Erwin and co-workers... 

The phenol-water extraction method can contain small amounts of lipoproteins that could confound experiments designed to measure only LPS biological activity. These contaminating proteins can be removed by an alternative procedure described below, which incorporates proteinase degradation prior to... 

The water extraction method, as used for alumina synthesis by Liu and Mlcox [167], was also successfully used by them for mullite synthesis a mixed colloidal sol of alumina and silica was used as the water phase. 

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