Chromate(5-), bis[4-(hydroxy-κO)-7-[2-(2-hydroxy-1-naphthalenyl)diazenyl]-3-[2-[2-(hydroxy-κO)- 3-nitro-5-sulfophenyl]diazenyl]-2-naphthalenesulfonato(4-)]-, sodium (1:5)

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

Pow

Partition coefficient:

< 0

Temp.:

20 °C

Remarks on result:

other: as not in applicability range of flask-method, interpreted as estimated value

Key result

Type:

log Pow

Partition coefficient:

< -5.9

Temp.:

20 °C

Remarks on result:

other: as not in applicability range of flask-method, interpreted as estimated value

During the preliminary test 1, the solubility of the test substance in n-octanol was determined to be 10 x 10^-3 g/l. No significant differences were observed between the concentrations analysed after the second and third centrifugation step. The available water solubility of test item was 400 g/l.

Hence, the partition coefficient Pow was estimated to be 2.5 x 10^-5 (log Pow = -4.6).

During preliminary test 2, it was observed that the n-octanol phase was coloured red/brown. The colour of the test substance is black/blue. During preliminary test 1, the n-octanol was coloured blue. It was assumed that the red/brown colour of the n-octanol phase derived from an impurity from the test substance with a higher log  Pow than the main component. This impurity showed no absorption at the detection wavelength used for the HPLC analysis and did not interfere with the analyses.

As the mean value of both measurements was not within the applicability range of the flask-shaking method, the main study was not performed and the result has to be interpreted as an estimated value.

Conclusions:

The partition coefficient (n-octanol/water) of test item was estimated to be < 1.2 * 10^-6 (log Pow < -5.9), using the flask-shaking method.

Executive summary:

In order to evaluate the partition coefficient of the test substance between n-octanol and water, a study was conducted using flask-shaking method, according to the method A. 8 of EEC-Directive 92/69 EEC. The partition coefficient (n-octanol/water) of test item was estimated to be < 1.2 * 10^-6, as a mean value of both measurements. Because this value was not within the applicability range of the flask-shaking method, the main study was not performed and the result has to be interpreted as an estimated value.

Description of key information

Log Pow < -5.9 (Pow < 1.2 x 10^-6) at 20 °C

Additional information

In order to evaluate the partition coefficient of the test substance between n-octanol and water, a study was conducted according to the method A. 8 of EEC-Directive 92/69 EEC.

The partition coefficient (n-octanol/water) of test item was estimated to be < 1.2 * 10^-6, using the flask-shaking method (log Pow < -5.9).