Trisodium bis[3-hydroxy-4-[(2-hydroxy-1-naphthyl)azo]naphthalene-1-sulphonato(3-)]chromate(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:

February from 12 to 26, 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

Reason / purpose for cross-reference:

reference to other study

Remarks:

validated analytical method

Qualifier:

according to guideline

Guideline:

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

Guideline:

other: OECD Guideline 105 (Water Solubility)

GLP compliance:

yes (incl. QA statement)

Type of method:

estimation method (solubility ratio)

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

Pow

Partition coefficient:

0.024

Temp.:

20 °C

Remarks on result:

other: estimated from individual solubilities

Type:

log Pow

Partition coefficient:

-1.62

Temp.:

20 °C

Remarks on result:

other: estimated from individual solubilities

Details on results:

The recovery rate of the measured standard solutions was in the range from 98.0 to 102.4 %, which shows a good accuracy of the analytical method.

PRELIMINARY TEST
The preliminary test at room temperature showed that the 1-octanol solubility of the test item was < 0.063 g/l.
Considering the values of the water solubility determined in specific experiment (i.e. 132.92 g/l at ca 20 °C, see IUCLID section 4.8) and the estimated solubility in octanol, the logarithm to base 10 of the partition coefficient can be supposed to be below -2.

Conclusions:

log Pow: -1.62 at 20 °C

Executive summary:

The partition coefficient octanol/water of test item was determined according to OECD guidelines 105 and 107 from the individual solubilities in water and octanol. The preliminary test at room temperature showed that the 1-octanol solubility of the test item was < 0.063 g/l. Considering the values of the water solubility determined in specific experiment (i.e. 132.92 g/l at ca 20 °C, see IUCLID section 4.8) and the estimated solubility in octanol, the logarithm to base 10 of the partition coefficient can be supposed to be below -2. Therefore, the partition coefficient was estimated from the individual solubilities.

For the main test three flasks were prepared with an amount of test item and 1-octanol, and one flask only with 1-octanol (blank). After stirring and centrifugation the 1-octanol phases were measured by means of HPLC. To verify the accuracy of the analytical method a fresh prepared standard solution (prepared with the test item) was measured in between the samples of the flask method. The recovery rate of the measured standard solutions was in the range from 98.0 % to 102.4 %, which shows a good accuracy of the analytical method.

The partition coefficient was calculated to be 0.0238 (i.e. log Pow: -1.62) at ca 20 °C.

Conclusion

log Pow: -1.62 at 20 °C

Description of key information

log Pow: -1.62 at 20 °C

Key value for chemical safety assessment

Log Kow (Log Pow):

-1.62

at the temperature of:

20 °C

Additional information

OECD 107 and 105 - individual solubilities