Cuprate(6-), [2-[[[[3-[[4-chloro-6-[[4-[[4-chloro-6-[(3-sulfophenyl)amino]-1,3,5-triazin-2-yl]amino]-2,5-disulfophenyl]amino]-1,3,5-triazin-2-yl]amino]-2-hydroxy-5-sulfophenyl]azo]phenylmethyl]azo]-5-sulfobenzoato(8-)]-, pentasodium hydrogen, (SP-4-3)-

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

May 19, 2016 - August 12, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

Principles of method if other than guideline:

Preliminary visual estimation of the n-octanol solubility
In a simple preliminary test mixtures of n-octanol and test item are prepared and visual assessed.

Main test: n-Octanol solubility of the test item
The saturation concentration of the test item in n-octanol is determined by means of the flask method (based the European Commission Regulation (EC) No. 440/2008, A.6. water solubility and the OECD Guideline 105). For the final calculation of the partition coefficient the water solubility of the test item determined in project 20160154.03 is used.
The quantity of test item necessary to saturate the desired volume of n-octanol is estimated from the preliminary visual test. About five times of the estimated solubility is weighed into each of three glass vessels fitted with glass stoppers. After adding a defined volume of n-octanol the batches are stirred at 30 °C in tightly closed flasks for different times (24 h, 48 h and 72 h). After equilibration (further stirring for 24 h at 20 °C) the suspensions are taken and prepared for the analytical determination.
Another experiment is performed according to this procedure but without test item (“blank”).

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

< -6.6

Temp.:

20 °C

Remarks on result:

not determinable

Remarks:

test substance is highly water soluble

 Preliminary visual estimation of the n-octanol solubility

Defined amounts of the test item were stirred with increasing volumes of n-octanol at room temperature and visually checked for any undissolved parts.

Table4: Results of the preliminary visual estimation of the n-octanol solubility

Amount of test item / mg	Added volume of n-octanol / mL	Total volume of n-octanol / mL	Stirring time / h	Appearance of mixture
0.9	10	10	2	not dissolved
	90	100	16.5	not dissolved

According to this preliminary test the solubility of the test item in n-octanol was below 90 mg/L (without correction for the purity).

Calculation of the partition coefficient log P_OWfrom the preliminary test

The partition coefficient P_OWmay be estimated from the saturation concentrations in n-octanol and water.

The estimated partition coefficient was calculated with the water solubility data determined in project 20160154.03 (c_S = 205 g/L). It was calculated to be: log P_OW < -3.4.

Also the program KOWWIN (part of EPI Suite) was used for calculating the log P_OWof the test item. The calculated value was -2.7.

Due to the calculations the partition coefficient was estimated based on the ratio of the solubilities in water and octanol. The octanol solubility was determined using the flask method.

 

Determination of the solubility in n-octanol: Flask method

The individual saturation solubility of the test item in n-octanol, based on the flask method described in the OECD guideline 105, was performed within this study. After that, the partition coefficient was estimated based on the ratio of the test item solubility in n-octanol and water (determined in project 20160154.03) according to equation (1).

The n-octanol solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in Table 5.

Table 5: n-Octanol solubility experiments of the test item

Experiment	24 h experiment	48 h experiment	72 h experiment	blank experiment (72 h)
Amount of test item / mg	4.4	4.0	4.4	--
Amount of octanol / mL	50	50	50	50
Stirring time at 30 °C / h	24	48	72	72
Aliquot of the flasks /mL	4	4	4	4
Volume of the aqueous phase used for the extraction / mL	1	1	1	1
Concentration factor	4	4	4	4
Aliquot of extracted phase / mL	0.5	0.5	0.5	--
Dilution factor	2	2	2	2
Measured concentration / mg/L	< 0.09954 / < 0.09954	< 0.09954 / < 0.09954	< 0.09954 / < 0.09954	-- / --
Mean concentration / mg/L	< 0.09954	< 0.09954	< 0.09954	--
n-Octanol solubility / µg/L	< 50	< 50	< 50	--

The n-octanol solubility of the test item at 20 °C was determined to be< 50 µg/L.

Calculation of the partition coefficient log P_OWfrom the individual solubilities

In theproject 20160154.03 the water solubility of the test item at 20 °C was determined to be 205 g/L (± 30 g/L). Within this project the n-octanol solubility of the test item at 20 °C was determined to be< 50 µg/L.

The partition coefficient P_OWwas estimated from the individual solubility in n-octanol and water.

The partition coefficient P_OWof the test item was determined to be: log P_OW< -6.6

Executive summary:

The partition coefficient (n-octanol/water) was estimated based on the ratio of the individual solubilities of the test item in water and n-octanol. The solubilities were determined according to the “flask method”. The partition coefficientlog P_owof the test item at 20 °C was determined to be:

log P_OW< -6.6

Description of key information

The partition coefficient (n-octanol/water) was estimated based on the ratio of the individual solubilities of the test item in water and n-octanol. The solubilities were determined according to the “flask method”.

The partition coefficientlog P_owof the test item at 20 °C was determined to be:

log P_OW< -6.6

Key value for chemical safety assessment

Log Kow (Log Pow):

-6.6

at the temperature of:

20 °C