Fraction of organic phase

Finally, it should be pointed out that a very critical part of a practical extraction system, with respect to overall dispersion or dilution of the sample zone, is the phase separator [1372]. Thus, Karlberg [116] found an almost linear relationship between the peak height and the fraction of organic phase transported to the flow cell, which observation emphasizes the importance of the incorporation of an efficient phase separator. Separators of the membrane type seem to be preferred for flow-injection... 

Enzymatic oxidation of ethanol and butanol Alcohol oxidase Toluene Conversion increases with increasing volume fraction of organic phase Hidaka et al. (1995)... 

The known models for describing retention factor in whole variable space ar e based on three-phase model and containing from three to six par ameters and variety combinations of two independent factors (micelle concentration, volume fraction of organic modifier). When the retention models are comparing or the accuracy of fitting establishing, the closeness of correlation coefficient to 1 and the sum of the squared residuals or the sum of absolute deviations and their relative values is taken into account. A number of problems ar e appear in this case ... 

In accordance with Eq. (3.4) or Eq. (3.6), the concentration selectivity of ion exchange is variable depending on the degree of ideality of the solution and CP phase. For dilute solutions at a constant ionic strength, it is possible to take into account as a variable only the degree of non-ideality of the CP phase. For the systems considered here, it is convenient to study the effect of the molar fraction of organic counterions (NJ on the concentration selectivity constant. Fig. 14 shows the dependences of Ks on the molar fraction of oxytetracycline in CP. For CP... 

The most common method for varying the chromatographic selectivity for neutral molecules in RPC is to change the type of organic modifier in the mobile phase. In numerous studies using binary mobile phases, equation (4.15) has been shown to describe reasonably well the variation of solute retention with the volume fraction of organic solvent in an aqueous-organic mobile phase... 

DHS can significantly affect the environmental behavior of hydrophobic organic compounds and lower the possibility of direct contact of such organic compounds with various solid phases. The rate of chemical degradation, photolysis, volatilization, transfer to sediments/soils, and biological uptake may be different for the fraction of organic pollutant that is bound to DHS. If this is the case, the distribution and total mass of a pollutant in an ecosystem depends, in part, on the extent of humic matter-hydrophobic binding. 

A large, sealed fish tank - consisting of 20 m of water, 10 m of air, 1 m of sediment, and 0.2 m of fish and other biological organisms - has 100 g of benzene accidentally spilled into it. What will be the eventual (equilibrium) concentrations and mass in each phase The fraction of organic carbon in the sediments has been determined to be 0.01. The density of the sediments has been determined to be 2g/cm. The octanol-water partitioning coefficient for benzene is 138. 

Electrospray requires low-ionic-strength solvent so that buffer ions do not overwhelm analyte ions in the mass spectrum. Low-surface-tension organic solvent is better than water. In reversed-phase chromatography (Section 25-1), it is good to use a stationary phase that strongly retains analyte so that a high fraction of organic solvent can be used. A flow rate of 0.05 to 0.4 mL/min is best for electrospray. 

The lipid organization in equimolar mixtures of cholesterol, synthetic CER, and free fatty acids closely resembles that in stratum corneum, as both LPP (12.2 nm) and SPP (5.4 nm) are present, the lateral packing of the lipids is orthorhombic, a minor fraction of cholesterol phase separates into crystalline domains, and no additional phases can be detected. Interestingly, free fatty acids are required for proper lipid organization, as only in their presence a dominant formation of the LPP could be detected. This might be related to the limited acyl chain length distribution present in these CER mixtures. 

It may be deduced from KP = Koc x foc that partition coefficients of hydro-phobic organic compounds in general are dependent upon the chemical of interest (compound-specific properties affect the value of Koc) and the matrix properties of the medium in which it resides. In addition to the fraction of organic carbon present in the sorption phase, additional environmental factors affect partitioning. These factors include temperature, particle size distribution, the surface area of the sorbent, pH, ionic strength, the presence of suspended material or colloidal material, and the presence of surfactants. In addition, clay minerals may act as additional sorption phases for organic compounds. Nevertheless, organic carbon-normalized partition... 

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