PARTITION COEFFICIENT

Partition coefficient

Partition coefficient (log10 PoW)

Partition coefficient //63

Partition coefficient n/octanol/water

Partition coefficient n-octanol/water

Partition coefficient n-octanol/water including effect of pH (4 to 10)

Partition coefficient N-octanol/water including effect of pH (5 to 9) and temperature (;)

Partition coefficient n-octanol/water including effect of pH (5 to 9) and temperature (7)

(m) Pow partition coefficient octanol/water.

Water partition coefficient (Log Po/w, etc.).

octanol/water partition coefficient,

octanol/water partition coefficient;

Preliminary estimate of the partition coefficient

- the preliminary assessment of the partition coefficient (see above),

Partition coefficient:

The partition coefficient is deduced from the capacity factor k, given by the expression:

The determination of the partition coefficient should be carried out with high purity analytical grade reagent.

where P ow (PhX) is the partition coefficient of an aromatic derivative and P ow (PhH) that of the parent compound

Normally, the partition coefficient of a compound can be estimated to within ± 1 log unit of the shake-flask value.

If there is a suggestion of concentration dependency of the partition coefficient, this should be noted in the report,

From the correlation graph of the reference compounds, the partition coefficient of the test substance can be interpolated.

oil/water coefficient of partition (1).

Such deviations are indicated by the fact that the partition coefficient becomes dependent upon the concentration of the solution.

The value of the partition coefficient can be estimated by the use of the solubilities of the test substance in the pure solvents:

Before carrying out either of the experimental procedures a preliminary estimate of the partition coefficient should first be obtained.

The determined values of the partition coefficient expressed as their common logarithms should fall within a range of ± 0,3 log units.

For the determination of the partition coefficient, it is necessary to determine the concentrations of the test substance in both phases.

The concentration of this stock solution should be precisely determined before it is employed in the determination of the partition coefficient.

The partition coefficient (P) therefore is the quotient of two concentrations and is usually given in the form of its logarithm to base 10 (log P).

Before a partition coefficient is determined, the phases of the solvent system are mutually saturated by shaking at the temperature of the experiment.

This enables the relationship between the retention time on such a (reverse phase) column and the n-octanol/water partition coefficient to be established.

- the calculated values of the partition coefficient (P) and the mean should be reported for each set of test conditions as should the mean for all determinations.

Sorption can be estimated by log Pow (partition coefficient octanol/water), where Pow < 2 is considered as low sorption', Pow < x < 4 is 'medium sorption' and Pow > 4 is 'high sorption'.

The partition coefficient (P) is defined as the ratio of the equilibrium concentrations (c i ) of a dissolved substance in a two-phase system consisting of two largely immiscible solvents.

The partition coefficient is estimated preferably by using a calculation method (see Appendix 1), or where appropriate, from the ratio of the solubilities of the test substance in the pure solvents (10).

Mixtures of chemicals are eluted in order of their hydrophobicity, with water-soluble chemicals eluted first and oil-soluble chemicals last, in proportion to their hydrocarbon-water partition coefficient.

In order to determine a partition coefficient, equilibrium between all interacting components of the system must be achieved, and the concentrations of the substances dissolved in the two phases must be determined.

In order to assure the accuracy of the partition coefficient, duplicate determinations are to be made under three different test conditions, whereby the quantity of substance specified as well as the ratio of the solvent volumes may be varied.

For very low and very high partition coefficients, extrapolation is necessary.

The HPLC method enables partition coefficients to be estimated in the log P ow range 0 to 6.

Additional information (for instance structural formula, degree of purity, nature and percentage of significant impurities, presence and amount of additives, and n-octanol/water partition coefficient) should be taken into consideration in both the planning of the test and interpretation of the results.

Additional information (for instance structural formula, degree of purity, nature and percentage of significant impurities, presence and amounts of additives, and n-octanol/water partition coefficient) should be taken into consideration in both the planning of the test and interpretation of the results.

If data on the partition coefficients of structurally related compounds are not available, then a more general calibration, established with other reference compounds, may be used.

Pow - partition coefficient octanol/water;

Water partition coefficient (Log Po/w, etc.).

the preliminary assessment of the partition coefficient (see above),