Reaction products of 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid, coupled twice with diazotized 2-[(4-aminophenyl)sulfonyl]ethyl hydrogen sulfate, sodium salts

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Deviations:

no

GLP compliance:

no

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

< -4.34

Temp.:

20 °C

Remarks on result:

other: pH not available

Details on results:

The partition coefficient Pow may be estimated from the saturation concentrations in n-octanol and water by the following equation:
Pow = cs (octanol) / cs (water) (2)
c = saturation
With the data obtained from the experiments in chapter 4.5.1 (cs < 24.9 mg/l) and in the preliminary test in project 20090683.04 (cs = 211 g/l to 1056 g/l) the partition coefficient was calculated as log Pow in the range of -3.9 to -4.6.
Additionally the log Pow (n-octanol/water) was calculated as log Pow = -4.1 using the program EPI Suite.
Due to the fact, that the log Pow is below -2, the partition coefficient n-octanol/water has to be estimated from the individual solubilities in water and n-octanol.
Table 2: Solubility of the test item – experiments A to D
Experiment A B C D (blank)
Amount of test item
(mg) 19.05 19.44 20.61 0
Stirring time at 30 °C
(h) 24 48 72 72
Aliquot of the sample1) (ml) 8 8 8 10
End volume1)
(ml) 2 2 2 2
Dilution with the Eluent
(ml) 0.2 to 1 0.2 to 1 0.2 to 1 0.2 to 1
Measured concentration (µg/l) < 5.57 / < 5.57 < 5.57 / < 5.57 < 5.57 / < 5.57 -- / --
Mean concentration (mg/l) < 0.006 < 0.006 < 0.006 --
Solubility
(mg/l) < 0.01 < 0.01 < 0.01 --
1) As the aliquots of the n-octanol phase could not be mixed with the HPLC-eluent, the test item in the n-octanol phase was extracted with dist. water. In each case 8 ml of the n-octanol phase were extracted with 2 ml water by means of a separating funnel.
4.1.3. Individual Solubility in Water
The individual solubility of the test item in water was taken from the main test in project 20090683.04. In this project the water solubility was determined according to the European Commission Regulation (EC) No. 440/2008, A.6. Water solubility, flask-method and the OECD test guideline 105 (1995) Water solubility.
The water solubility cs of the test item at a temperature of 20 °C was determined to (without correction for the purity):
cs > 551 g/l

POW= cs^n-octanol/ cs^water	POW	log POW
< 24.9 mg/l /> 551 g/l	4.52 x 10^-5	< - 4.34

Conclusions:

The partition coefficient n-octanol/water of the test item at 20 °C, estimated from the individual solubility in water and n-octanol, was determined to be log Pow <-4.3

Executive summary:

The partition coefficient n-octanol/water of the test item at 20 °C, estimated from the individual solubility in water and n-octanol, was determined to be log P_OW < -4.3 according to OECD guideline 107.

Description of key information

The partition coefficient n-octanol/water of the test item at 20 °C, estimated from the individual solubility in water and n-octanol, was determined to be log POW <- 4.3 according to OECD guideline 107.

Key value for chemical safety assessment

Log Kow (Log Pow):

-4.3

at the temperature of:

20 °C