Disodium 3-[[4-amino-9,10-dihydro-9,10-dioxo-3-[sulphonato-4-(1,1,3,3-tetramethylbutyl)phenoxy]-1-anthryl]amino]-2,4,6-trimethylbenzenesulphonate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From February 20 to March 20, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1995

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - Shake Flask Method)

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

Pow

Partition coefficient:

-1.3

Temp.:

25 °C

pH:

ca. 6

Details on results:

To verify the accuracy of the analytical method two fresh prepared standard solutions in double distilled water (prepared with the test item) were measured in between the samples of the shake-flask-method. The recovery rate of the measured standard solutions was in the range from 101.6 % to 108.9 %, which shows a sufficient accuracy of the analytical method.

PRELIMINARY TEST
The preliminary test at room temperature showed, that the octanol solubility of the test item was between 0.1 and 0.9 g/l.
With the water solubility of 36.3 g/l at 20 °C, determined in the specific study and the solubility in octanol between 0.1 and 0.9 g/l, determined from this preliminary test, the partition coefficient can be estimated to be between -2.4 and -0.9.

Results of the shake-flask-method

separating funnel	total amount of test item in the separating funnel (mg)	recovery rate (%)	POW	log POW
1a	11.0	100.6	0.05	-1.3
1b	10.7	97.8	0.05	-1.3
2a	10.7	98.0	0.04	-1.4
2b	10.7	97.8	0.05	-1.3
3a	10.7	98.3	0.05	-1.3
3b	10.4	95.1	0.06	-1.2
mean value				-1.3
standard deviation				<0.1

Concentrations in the aqueous phases

separating funnel	pH values^*	measured concentration (mg/l)	mean concentration^**(mg/l)
1a	6.0	26.6 / 26.9	267.2
1b	6.0	26.0 / 25.9	259.5
2a	5.9	25.7 / 25.4	255.8
2b	6.0	25.2 / 25.7	254.6
3a	5.8	48.7 / 48.7	486.7
3b	5.9	46.4 / 46.3	463.8

*at temperatures of 24.6 – 24.8 °C

**under consideration of the dilution factor 10

Concentrations in the octanol phases

separating funnel	measured concentration (mg/l)	mean concentration (mg/l)
1a	13.7 / 13.4	13.6
1b	14.0 / 14.0	14.0
2a	11.1 / 11.3	11.2
2b	11.9 / 12.0	11.9
3a	24.7 / 24.2	24.5
3b	27.2 / 27.5	27.4

Conclusions:

log Pow: -1.3 at 25 °C and pH ca 6

Executive summary:

The partition coefficient was determined following the method and procedures described into the OECD guideline 107.

Based on the preliminary test results, the partition coefficient was estimated to be between -2.4 and -0.9, thus shake-flask method was used for the main experiment.

For the shake-flask-method six separating funnels were prepared. After adding the different amounts of stock solution, pre-saturated double distilled water and pre-saturated 1-octanol, the funnels were shaken for approx. 10 minutes in a shaking apparatus. After shaking the phases were allowed to separate in the funnels. Subsequently, 10 ml of each phase were centrifuged for 30 minutes at 20 °C and 15000 rpm.

For the analytical measurement by means of HPLC the centrifuged clear aqueous phases were diluted from 0.1 to 1 ml with double destilled water. The octanol phases were not diluted for the HPLC-measurements. The pH values of all water phases were measured.

The log Pow values of all six separating funnels should lie within the range of ±0.3 units.

The partition coefficient log Pow resulted to be -1.3 (SD < 0.1) at 25 °C and pH ca 6.

To verify the accuracy of the analytical method two fresh prepared standard solutions in double distilled water (prepared with the test item) were measured in between the samples of the shake-flask-method. The recovery rate of the measured standard solutions was in the range from 101.6 % to 108.9 %, which shows a sufficient accuracy of the analytical method.

Conclusion

log Pow: -1.3 at 25 °C and pH ca 6

Description of key information

log Pow: -1.3 at 25 °C and pH ca 6

Key value for chemical safety assessment

Log Kow (Log Pow):

-1.3

at the temperature of:

25 °C

Additional information

OECD 107 - Shake-flask method