Partial extraction

Partially extracted Raney cobalt is very active, but it is easily poisoned by sulfur and tends to lay down carbon more readily than Raney nickel (21). Cobalt is less active than nickel and much less selective to methane... 

In general, a decrease in enantioselectivity was observed after the second reuse. The origin of this effect lies in the partial extraction of the chiral hgand in the hexane phase after each reaction. This was demonstrated by adding a small amount of ligand after the fourth reuse. In all cases, the original enantioselectivity was fully recovered (entries 2 and 3 in Table 6). 

The PemB cellular localisation was determined both in E. chrysanthenu and in an E. coli recombinant strain by Western blot of the cell fractions with a PemB-antiserum. No PemB was detected in the culture supernatant and only trace amounts were found in the soluble cell fractions - periplasm and cytoplasm (Figure 2). PemB was found mostly in the total membrane fraction from which it could be completely extracted by Triton X-100/Mg2+ and partially extracted by Sarkosyl (Figure 2). This behaviour is typical of inner membrane proteins, but since some exceptions have been noticed it does not positively indicate the PemB localisation (15). We performed cell membrane fractionation in sucrose density gradient centrifugation both by sedimentation and flotation, using several markers of inner and outer membrane vesicles. PemB was found in the outer membrane vesicles (data not shown). 

Often, it is not possible to extract one solute quantitatively without partial extraction of another. The ability to separate two solutes depends on the relative magnitudes of their distribution ratios. For solutes A and B, whose distribution ratios are DA and DB, the separation factor P is defined as the ratio DA/DB where D>DB. Table 4.2 shows the degrees of separation achievable with one extraction, assuming that Da = 102, for different values of DB and P. For an essentially quantitative separation P should be at least 105. 

This paper documents a soil and till survey of the Shiko Lake porphyry copper-gold mineral occurrence near Quesnel Lake, British Columbia, and the comparison of Cu, Au, and other elements by partial extraction geochemical analysis with the distribution of gold and other heavy mineral grains (Lett Doyle 2009). 

Two commercial partial extraction techniques improve anomaly contrast in B horizon soil samples compared to aqua regia-ICPMS for Cu and Au. However, whereas the MMIsm and Bio LeachSM Cu profiles are similar, the MMIsm Au signal is much larger than that for Bio LeachSM. Analysis of samples at different depths down the B soil horizon profile indicates that the geochemical response from these methods is depth dependant. 

Partial extraction such as MMI analysis provides additional and distinct... 

Very low density sampling can provide reliable, representative geochemical information on a regional basis, with total and partial extraction data yielding complementary information. 

Keywords soil, partial extractions, gold, geochemistry... 

Data from the Na-pyrophosphate partial extractions and estimates of organic C contained in humic and fulvic acids from spectroscopic determinations show poor reproducibility over time. Analysis of data from re-sampling in September 2007 show significantly lower results over bedrock mineralisation than the original orientation survey conducted in April 2007, although the general pattern appears to be preserved. Re-analysis of the duplicate field samples in the same batch indicates that this variation largely reflects seasonal variations in metal content of the soils, possibly related to rainfall patterns, but also includes a component of laboratory variation between batches. 

An investigation of partial extractions designed to solubilize Pb and Zn from soils using a complexation desorption mechanism... 

Fig. 3. A N-S soil traverse of Zn concentrations obtained using a 1.0 M KF salt solution partial extraction.

Fig. 4. A N-S soil traverse of Pb concentrations obtained via partial extraction using a 0.01 M KBr salt solution.

Keywords SGH, hydrocarbons, partial extraction, deep penetrating organic geochemistry... 

Keywords sou geochemistry, partial extraction, selective extraction, Matagami, Perseverance zinc deposit. 

Some hemicelluloses are partially extractable with water, but they are usually extracted with alkaline solutions following removal of lipids and lignin. Delignified plant material is termed, holocellulose. Neutralization of the alkaline extract effects precipitation of the more linear and less acidic hemicelluloses, termed the hemicellulose A [63100-39-0] fraction. The more acidic and more branched material, termed hemicellulose B [63100-40-3], is precipitated with ethanol (70%). Hemicellulose B types type are usually water-soluble after extraction. 

T,he original report by Barrer and Makki (1) that aluminum in a high A silica zeolite, clinoptilolite, could be extracted with mineral acid to give a silica pseudomorph, has given rise to considerable research on acid-extracted mordenite (2-6). Hydrogen mordenite is useful as an adsorbent and a catalyst, and its properties for some purposes are improved by partial extraction of the aluminum. Further, the ability to vary aluminum content while maintaining crystallinity offers the opportunity to leam more about the nature of the active sites in mordenite. 

The primary separation of plutonium and uranium from the fission products involves a solvent extraction with 30 vol % TBP at room temperature. The activity levels in this separation are quite high ( 1700 Ci/L for the fission products) and the aqueous waste, which contains 99+% of the fission products, is a high-level waste. Am and Cm are not extracted and Np is partially extracted. Because of the high radiation levels, there are radiolysis problems with TPB, leading to solvent degradation. Primary products of the radiolysis of TBP are the dibutyl- and monobutylphosphoric acids along with phosphoric acid. These degradation products are removed in the solvent purification steps. 

Water-containing plant materials need to be extracted with polar solvents such as acetone, methanol, or ethanol that can take up water. Freeze-dried plant tissues and freeze-dried juices can be directly extracted with diethyl ether, which contains traces of water and is more polar than light petrol or hexane. Pure light petrol or hexane are less suitable, because more polar pigments, such as Chi b or xantho-phylls, are only partially extracted from freeze-dried plant samples. A few drops of acetone or ethanol added to light petrol or hexane will, however, guarantee a complete extraction. This mixture will extract Chi a, Chi b, and all carotenoids—including xanthophyll esters and secondary carotenoids that are present in many fruits and juices—from the freeze-dried plant material. 

Of the two techniques described here, simultaneous distillation extraction (SDE) is a more complete volatile extraction procedure that serves to obtain quantitative information on the compounds contained in a food. Volatile trapping is a partial extraction procedure that samples the vol a-tiles present in the headspace above a food, which are those with higher volatili ty. Extended trapping also induces additional volatilization of compounds initially contained in the food. 

The herbs and spices may be placed in cloth bags and suspended in the wine. After the first extraction, fresh base wine may be added for a second, and even a third extraction. Partial extractions are preferred, as complete extraction may result in the incorporation of undesirable flavors or aromas. This also avoids pressing the spent materials that is associated with the release of objectionable bitter flavors. 

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