Explore chapters and articles related to this topic
Modeling contaminant transport and biodegradation in groundwater
Published in Domy C. Adriano, Alex K. Iskandar, Ishwar P. Murarka, Contamination of Groundwaters, 2020
Hanadi S. Rifai, Philip B. Bedient
The partition coefficient, Kd, can be measured in static batch experiments or in dynamic column tests; however the “hydrophobic theory” (Karickhoff et al.., 1979 and Schwartzenbach and Westfall, 1981) provides a method to estimate this coefficient indirectly, within a factor of 2. For a neutral hydrophobic compound, one that is soluble in water, but more soluble in an organic solvent, a dimensionless partition coefficient, Kow, between water and n-octanol is first measured.
Feedstock Evaluation
Published in James G. Speight, Refinery Feedstocks, 2020
Chromatography is the collective term for a set of laboratory techniques for the separation of mixtures. Typically, the mixture is dissolved in a fluid (mobile phase) which carries it through a structure holding another material (stationary phase). The various constituents of the mixture travel at different speeds, causing them to separate. The separation is based on differential partitioning between the mobile and stationary phases. Subtle differences in the partition coefficient of different compounds result in differential retention on the stationary phase and thus changing the separation.
Basic Concepts of Exposure and Response
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
The partition coefficient is a measure of an agent’s distribution between an aqueous and lipid phase of a solution. It is an attempt to quantify, for comparison purposes, an agent’s lipid solubility. It is given by the expression: PartitionCoefficient=concentrationinlipidphaseconcentrationinaqueousphase A high partition coefficient means that a toxicant is lipophilic. A good correlation has been demonstrated for the partitioning of the alcohols and their speed of absorption. But this correlation has not been demonstrated for other types of agents. A very highly lipid-soluble agent may penetrate a membrane well but not exit. The size of the molecule is another important factor, too. Generally speaking, large water-soluble molecules (lipid insoluble) are poorly absorbed.
Performance and potential of bacterial biodegradation of polycyclic aromatic hydrocarbons from micellar solutions
Published in Environmental Technology Reviews, 2021
An alternative approach to quantifying the solubilization capacity of surfactants is the micelle-water partition coefficient (Km). The Km is the ratio of mole fraction of the PAH within the micellar pseudo phase (Xm) to the mole fraction of PAH in the aqueous pseudo phase (Xa), and it can be determined by the following relation [108]; The value of micellar mole fraction of PAH can be correlated from the MSR as follows; The mole fraction of PAH in dilute solutions can be calculated as; Where SPAH,CMC is the apparent solubility of PAH at the CMC in mol/L and Vw is the molar volume of water at the experimental temperature (L/mol).
Spectroscopy, docking and molecular dynamics studies on the interaction between cis and trans palladium-alanine complexes with calf-thymus DNA and antitumor activities
Published in Journal of Coordination Chemistry, 2023
Asma Izadyar, Hassan Mansouri-Torshizi, Effat Dehghanian, Somaye Shahraki
The lipophilicity of biologically active compounds has a special effect on their capacity to cross trough cell membranes. The partition coefficient of the above complexes was measured to see if there is a relationship between this parameter and cell membrane permeability [52]. Lipophilicity is expressed by the partition coefficient (log P), which is a molecular parameter and is expressed through the equilibrium between an aqueous solvent and an organic solvent such as n-octanol. The partition coefficient is actually the concentration ratio of a compound in the two phases of water/octanol. A positive log P (Equation (1)) value indicates the tendency to lipid phase and a negative log P value indicates relative affinity for the aqueous phase [53].