Extraction fractionation

Most purification procedures for a particular protein are developed in an empirical manner, the overriding principle being purification of the protein to a homogeneous state with acceptable yield. Table 5.5 presents a summary of a purification scheme for a selected protein. Note that the specific activity of the protein (the enzyme xanthine dehydrogenase) in the immuno-affinity purified fraction (fraction 5) has been increased 152/0.108, or 1407 times the specific activity in the crude extract (fraction 1). Thus, xanthine dehydrogenase in fraction 5 versus fraction 1 is enriched more than 1400-fold by the purification procedure. 

Figure 4 Mole percentage of comonomer and intrinsic viscosities of a 1-butene LLDPE (O) and an 1-octene LLDPE (A) and direct extraction fractions thereof ( ) and (A), respectively. Source Ref. 32.

Methods are described for determining the extent to which original natural color is preserved in processing and subsequent storage of foods. Color differences may be evaluated indirectly in terms of some physical characteristic of the sample or extracted fraction thereof that is largely responsible for the color characteristics. For evaluation more directly in terms of what the observer actually sees, color differences are measured by reflectance spectrophotometry and photoelectric colorimetry and expressed as differences in psychophysical indexes such as luminous reflectance and chromaticity. The reflectance spectro-photometric method provides time-constant records in research investigation on foods, while photoelectric colorimeters and reflectometers may prove useful in industrial color applications. Psychophysical notation may be converted by standard methods to the colorimetrically more descriptive terms of Munsell hue, value, and chroma. Here color charts are useful for a direct evaluation of results. 

The objective indication of color differences in foods has usually been attempted in a simplified, indirect way that involves a comparison of some physical characteristic of the samples or, more often, an extracted fraction that is assumed or has been proved to be largely responsible for the associated color characteristics. Although such a method does not measure the actual visual color of the samples, a measure of relative amounts of color-characteristic pigments or a comparison of physical properties of extracts of color-critical fractions (which may be mixtures of several pigments) may prove to be very sensitive indications of differences that are closely related to color. 

As is the case with assessments of the toxicity of dissolved trace metals, the development of sediment quality criteria (SQC) must be based on the fraction of sediment-associated metal that is bioavailable. Bulk sediments consist of a variety of phases including sediment solids in the silt and clay size fractions, and sediment pore water. Swartz et al. (1985) demonstrated that the bioavailable fraction of cadmium in sediments is correlated with interstitial water cadmium concentrations. More recent work (e.g., Di Toro et al, 1990 Allen et al., 1993 Hansen et al, 1996 Ankley et ai, 1996, and references therein) has demonstrated that the interstitial water concentrations of a suite of trace metals is regulated by an extractable fraction of iron sulfides. 

S] + K )] for the hexokinase-catalyzed phosphorylation reactions of 2DG and D-glucose, respectively [S (substrate) + E (enzyme) — ES— -I- P (product)]. This constant (LC) accounts for the ratio of the arteriovenous extraction fraction (by transport and phosphorylation) of 2DG to that of D-glucose (LC= 1) under steady-state conditions. This concept can be directly applied to the case of 2DFG by employing the LC (-0.5) for 2DFG. 

CALDWELL c R (2001) Oxygen radical absorbance capacity of the phenolic compounds in plant extracts fractionated by high-performance liquid chromatography, ,4Biochem, 293, 232-8. 

Separation of the components of the previously extracted fractions (indicating the presence of active compounds) of... 

Kucesa J, Sychra V and Koubek J (1998) A set of four soil reference materials with certified values of total element contents and their extractable fractions. Fresenius J Anal Chem 360 402-405. 

The extracted fractions were esterified with either BF3-MeOH reagent or diazomethane and analyzed by GLC. Gas liquid chromatography (GLC) was conducted with a Perkin-Elmer Sigma 3 equipped with flame ionization detector. Separations were obtained on a Hewlett Packard 12 m x 0.2 mm i.d. capillary column coated with methyl silicon fluid (OV-101). The temperature was maintained at 80°C for 2 min then programmed from 80 to 220°C at 8°C/min. The injector temperature was 250°C. Mass spectra were obtained on a Hewlett Packard model 5995 GC-MS mass spectrometer, equipped with a 15 m fused silica capillary column coated with 5% phenyl methyl silicone fluid. Spectra were obtained for major peaks in the sample and compared with a library of spectra of authentic compounds. 

Table II - Antimicrobial Activity of Extracts, Fractions, and Compounds...

An SFE instrument can be designed as a single standalone instrument performing a range of manual processes extraction, fractionation, concentration, solvent exchange, reconstitution and derivatisation. 

Wate r/wastewate r pH adjustment to >11 solvent extraction fractionation on Florisil columns GC/MS Not specified Not specified Peterman et al. 1980... 

Unfortunately, many clinical studies evaluating the efficacy of dietary supplements are flawed. Some of the flaws in the studies include non-randomization, being unblinded, lack of standardized products, small sample sizes, short treatment durations, and poorly defined inclusion and exclusion criteria. Many studies do not give detailed information about the dietary supplement used. When an herb is studied, the following information should be described plant species, part(s) used, product form (e.g., powdered crude herb, aqueous extract, ethanol extract, or aqueous alcohol extract) with stated proportions of water to alcohol, specifically extracted fractions, and quantities or concentrations used [48]. 

To identify plasticisers in simple systems, often an IR spectrum of a methanol or acetone extract (after evaporation of solvent) will enable the positive identification of plasticiser type. For more complex systems it is necessary to initially separate the extractable fraction from the sample on for example a molecular weight basis (molecular size in solution). 

Deep desulfurization method of fossil fuels, comprising a first step of HDS and a BDS step for the removal of HDS sulfur refractory compounds, using an effective amount of a biocatalyst. The fuel is incubated in the presence of enzymes obtained as a lysate, extract, fraction or subfraction of one or more microorganisms. The organic sulfur compounds are converted into water-soluble inorganic sulfur. Then, the desulfurized liquid fossil fuel is separated from the aqueous medium. 

Martin et al. (2007a) investigated the accumulation and potential release of arsenic in a paddy field in Bangladesh irrigated with arsenic contaminated groundwater. The oxalate-extractable fraction related to amorphous hydrous oxide-bound arsenic represented the dominant arsenic form in the surface layer (47%). A high percentage of arsenic was removed by phosphate (22%). 

Figure 11. Camp Century, Greenland and Byrd Station, Antarctica ice cores COs contents of the first gas extraction fraction and S1S0 profiles (50). The S,sO profiles are from Dansgaard and coworkers, and the ages are calculated according to Ref. 54.

Several factors indicate that the amino acids detected in all of these carbonaceous chondrites are indigenous and that they must have originated abiotically. First, the presence of protein and non-protein amino acids, with approximately equal quantities of D and L enantiomers points to a nonbiological origin and precludes terrestrial contamination. In addition, the non-extractable fraction of the Murchison is significantly heavier in 13C than terrestrial samples. Finally, the relative abundances of some compounds detected resemble those of products formed in prebiotic synthesis experiments. The aliphatic hydrocarbons are randomly distributed in chain length, and the C2, C3, and C4 amino acids have the highest concentrations (i.e., the most easily synthesized amino acids with the least number of possible structures are most abundant) [4]. 

Cyclohexane extractable fractions coke oven emissions, 100.0-150.0 1... 

Heating the reaction for shorter periods gave erratic results. At this point the semisolid mixture can be diluted with 200 ml. of water, extracted with benzene, and the benzene extract fractionally distilled to give ethyl 2,3-dicyano-3-methylpentanoate, b.p. 146.0-147.5° (2.5 mm.), m27d 1.4429 (highly purified ester has b.p. 138.5-141.5° (2 mm.), 25d 1.4432). The overall yield of a-ethyl-a-methylsuccinic acid is decreased by about 5% when the dicyano intermediate is isolated. 

Heise and Litz [26] investigated the extraction behaviour of surfactants (LAS, NPEO and cationics) from sand comparing Soxhlet extraction, accelerated solvent extraction (ASE) and microwave-assisted extraction. Fractionation of the three surfactant types anionic, non-ionic and cationic, was accomplished by column chromatography with aluminium oxide. Soxhlet extraction and ASE of spiked sand with methanol—stored during 7 days prior to extraction—gave similar recoveries for both LAS and NPEO with values between 88 and 116%. Less efficient extraction was achieved by microwave extraction (79% for NPEO). 

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