Partitioning dependences

Like all other equilibrium constants, the value of / (partition) depends strongly on temperature. 

Comparing the lipophilicity of the barbiturates in Table 2.2 with their uptake across the GI tract (colon) demonstrates that the membrane permeability of each member of the series is proportional to its partition coefficient. Apparently, there can be some differential effect on partitioning depending upon which organic solvent is used in making the determination. For example, the GI membrane is believed to behave more like an octanol/water pairing, while drug uptake into the brain is more closely mimicked by a heptane/water combination. 

As for other chemical compounds,70 72 in the atmosphere the PCDDs, PCDFs and PCBs are partitioned14,22 23 30 38 39 41 44 45 47 51,62 73 between the gas and particle phases, with the gas/particle partitioning depending on the liquid-phase (or sub-cooled liquid-phase) vapour pressure at the ambient atmospheric temperature, PL, the surface area of the particles per unit volume of air (for example, cm2 of particle per cm3 of air), 6, and the nature of the particles and of the chemical being adsorbed.62,70,71 The fraction of the chemical present in the particle phase, 4>, depends on these parameters through an equation of the form62,70 72... 

Gas chromatography may be divided into gas solid chromatography (mainly adsorptive processes) and gas-liquid chromatography (mainly partition) depending on whether the stationary phase is a solid or a liquid at its operating temperature. If the stationary phase is a hquid it must be coated on a support for packed coliunn chromatography. For capillary column chromatography, the stationary phase may be coated directly on to the walls of the coliunn, or on to a support which is bonded to the... 

Noble gases exist in formation waters as uncharged, nonpolar species. They preferentially partition from aqueous solutions into nonpolar solvents such as crude oil and natural gas (Kharaka and Specht, 1988). The degree of partitioning depends on such factors as temperature, gas atomic radius, and the salinity of the aqueous phase. Distinct variations in Ne/ Ar, Kr/ Ar, and °Xe/ Ar are produced by fractionation in multiphase fluid systems. These variations have been used as a tool in oil exploration and reservoir evaluation. Pinti and Marty (2000) give detailed examples of these applications in the Pannonian Basin, Hungary and in the Paris Basin, France. 

Schultz, T.W. and Seward, J.R. (2000) Dimyristoyl phosphatidylcholine/water partitioning-dependent modeling of narcotic toxicity to Tetrahymena pyriformis. Quant. Struct. -Act. Rdat.,... 

Whereas salt partitioning depends equally on the natures of the cation and the anion, the exchange process has no formal dependence on the anion and describes only the cation selectivity. By studying Eqs. (33) and (42) separately, we can infer the exchange given by Eq. (43). If we label the exchange constant Xs-. n-m, it may readily be seen that Xs. n-m = Xs (NX)/X,(MX). 

Sorption and partition, depending on the physico-chemical properties of the substance, regulating the affinity for the organic or mineral component of the soil. 

MEKC uses the same instmment set-up as in conventional CE and uses uncoated capillaries. When a water-insoluble hydrophobic compound is added to a micellar solution, it partitions into the core of the micelle and is solubilized. Conversely, if a water-soluble hydrophilic compound is added to the solution it will solubilize in the aqueous phase and will not partition into the micelle. Neutral compounds of intermediate water solubility will partition between the aqueous phase and the micelle core and the extent of the partitioning depends on the hydrophobicity of the compound. When high pH micellar solutions are used as the carrier electrolyte in CE, the negatively charged micelles migrate in the opposite direction to the EOF but the more powerful EOF carries them to the cathode. 

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