Partitioning of compound

MEKC is a CE mode based on the partitioning of compounds between an aqueous and a micellar phase. This analytical technique combines CE as well as LC features and enables the separation of neutral compounds. The buffer solution consists of an aqueous solution containing micelles as a pseudo-stationary phase. The composition and nature of the pseudo-stationary phase can be adjusted but sodium dodecyl sulfate (SDS) remains the most widely used surfactant. 

A comprehensive study of the complex interfacial processes involved in the solvent extraction of cupric ion by oxime ligands represents one of the most detailed and successful studies carried out with the RDC [37,38]. Recently, the technique was also used to study the transfer of tetrabutylammonium cations [43] and the kinetics of partitioning of compounds between octanol and water [44]. In the latter study, Fisk and coworkers investigated the rates of partitioning of 23 compounds from octanol to an aqueous phase. The RDC arrangement used most frequently in this work is of the o/o/w type. So according to Eq. (15), and can be calculated from the gradient and intercept of... 

Both SPE and LLE involve a partitioning of compounds between two phases solid and liquid for SPE and two immiscible liquids for LLE. As modem SPE is a technique in which the basic principles of liquid chromatography are used to isolate the compound(s) of... 

Fig. 17.14. Separation principle in MECC. A compound (neutral or charged) is partitioned between the micellar and aqueous phase. A fully solubilized neutral compound migrates with the velocity of the micelles. A neutral compound with no affinity for the micelles migrates with the velocity of the EOF. A neutral compound with an affinity for both the micellar and the aqueous phase migrates with an intermediate velocity. (A) Schematic overview of the partitioning of compound (N the EOF moves toward the cathode and the typical SDS micelles toward the anode. (B) Diagram of the zone distribution within the capillary. (C) Reconstructed typical electropherogram.

Then, they considered both log P and HCPSA in MLR. It was interesting to find that the partitioning of compounds between the blood and... 

Xue, L. and Bajorath, J. (2002) Accurate partitioning of compounds belonging to diverse activity classes../. Chem. Inf. Comput. Sci. 42, 757-764. 

This method is based on the partitioning of compounds between a sample and a coated fibre immersed in it [16-18]. The volatiles and other compounds are first adsorbed onto the fibre immersed in a liquid sample, an extract, or in the headspace above a sample for a certain period of time. After adsorption is complete, the compounds are thermally desorbed into a GC injector block for further analysis. Particularly in food applications, headspace SPME is preferred to avoid possible contamination of the headspace system by non-volatile food components [16]. 

The partitioning of compounds among the different phases leads to a stripping of substrates or products, creating emission of volatile organic compounds... 

In these chapters, we focus on equilibrium situations and the associated problem of calculating the distribution of a compound between the different phases, when no net exchange occurs anymore. There are many situations in which it is correct to assume that phase transfer processes are fast compared to the other processes (e.g., transformations) determining a compound s fate. In such cases, it is appropriate to describe phase interchanges with an equilibrium approach. One example would be partitioning of compounds between a parcel of air and the aerosols suspended in it. Another case might be partitioning between the pore water and solids in sediment beds. 

Even low growth rates can significantly affect the measured partitioning of compounds, particularly those with high Kow. When the growth rate is 0, the slope of the BAF(lip)-K0W relationship is 1. However, as the growth rate increases there is a rapid drop in the BAF(lip) of high-K0W compounds. The result is an apparent plateau in the BAF(lip)-K0W relationship. Further in-... 

Semi-volatile organohalogen compounds, such as PBDEs, exist in the atmosphere in the gas-phase or associated with the particle-phase. The partitioning of compounds between these atmospheric phases is an important factor in their subsequent fate, transport, degradation, and human exposure assessment. Particle-to-gas partitioning is controlled largely by the physical properties of a compound, such as its vapor pressure and by the prevailing environmental conditions, such as the atmospheric temperature. As noted above, in the Strandberg et al. study, the samples were selected from days when the atmospheric temperature was 20 3 °C [42], At this temperature, the PBDEs were present in both the particle- and gas-phases, except for BDE-209, which was present only in the particle-phase. 

The ff-moment approach has proved to be a very robust and valuable tool for the analysis of the partitioning of compounds between most diverse phases. A typical application is logi oc, the logarithmic soil sorption coefficient, which is of crucial importance in environmental exposition and distribution models. Since the experimental measurement of Koc is difficult, expensive, and often unreliable, good prediction models are especially important here. On the basis of a training set of 387 compounds collected by Winget et al. [110], we derived a COSMO-KOC model expressed as... 

The partition of compounds between water and air is given by the Henry s law constant, H, which may be defined as the ratio of a compound s vapour pressure to its solubility, as indicated in equation (1), or alternatively as the dimensionless equilibrium concentration in air over the corresponding concentration in water, Xaw (equation 2). 

The Kinetics of the Partitioning of Compounds Between Octanol and Water, and its Relationship to the Movement of Molecules in Biological Systems... 

This overview sets out the rationale for, and potential benefits of, studies of the kinetics of partitioning of compounds between immiscible phases. 

The kinetics of the partitioning of compounds between octanol and water Ch. 6... 

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