Trisodium 2-[[4-[[4-[(4-amino-6-chloro-1,3,5-triazin-2-yl)amino]-5-sulphonatonaphthyl]azo]-2,5-dimethylphenyl]azo]benzene-1,4-disulphonate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014

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

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

Test Item: FAT 40075/D
Lot no.: BOP 01-12

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

-3.46

Temp.:

20 °C

Remarks on result:

other: pH is not known

Details on results:

None

Preliminary visual estimation of the n-octanol solubility:

Different amounts of the test item were stirred with different amounts of n-octanol at room temperature and visually checked for any undissolved particles.

Table: Appearance of the test mixtures.

Amount of test item in mg	Volume in ml	Total volume in ml	Stirring time	Appeatance of mixture
100	10	10	60 min	undissolved
	50	50	60 min	undissolved
10	10	10	50 min	undissolved
	50	50	95 min	undissolved
	100	100	95 min	dissolved

According to this preliminary test the solubility of the test item in n-octanol is below 200 mg/l (without correction of the purity).

 

Calculation of the partition coefficient log Pow from the preliminary tests:

With the data obtained from the preliminary visual estimation of the n-octanol solubility (cs < 200 mg/l) and in the preliminary test (water solubility: cs = 334 g/l) the partition coefficient was calculated as log Pow below -3,2.

 

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.

 

Determination of the solubility in the n-octanol phase: Flask Methods

Experiment	A	B	C	D (blank)
Amount of test item (mg)	100	100	100	--
Stirring time at 30 °C (h)	24	48	72	72
Aliquot of the flasks (ml)	1	1	1	1
End volume (ml)	3	3	3	3
Measured concentration (μg/ml)	38.2	40.4	37.6	--
Solubility (mg/l)	114	121	113	--

 

The average of the measured concentrations of the test item in n-octanol was 116 mg/l.

 

Concentrations of standards for recheck:

Standard	Measured concentration (μg/ml)	% Recovery
Standard 1 (c=1.62 μg/ml)	1.64	101.2
Standard 2 (c= 8.10 μg/ml)	8.02	99
Standard 4 (c= 32.40  μg/ml)	31.99	98.7

 

Recovery ranged from 98.7 % to 101.2 % indicating a sufficient accuracy of the analytical method.

 

Calculation of the partition coefficient log P_ow from the individual solubility in water and n-octanol:

By means of the flask method, the saturation concentration of the test item in n-octanol was determined to: 116 mg/l.

By means of the flask method, the saturation concentration of the test item in water was determined to: 334 g/l.

Pow= cs^octanol/ cs^water	Pow	log  Pow
0.116 mg/l / 334 g/l	3.47E-4	-3.46

Conclusions:

The partition coefficient n-octanol/water of the test item at 20 °C, from the individual solubility in water and n-octanol, was determined to be -3.46 (log Pow).

Executive summary:

The partition coefficient n-octanol/water of the test item was determined using the flask method speficied in OECD Guideline 107. Based on the individual solubility of test item in n-octanol and water, the n-octanol/water partition coefficient was determined to be -3.46 (log Pow).

Description of key information

The partition coefficient n-octanol/water of the test item was determined using the flask method speficied in OECD Guideline 107. Based on the individual solubility of test item in n-octanol and water, the n-octanol/water partition coefficient was determined to be -3.46 (log Pow).

Key value for chemical safety assessment

Log Kow (Log Pow):

-3.46

at the temperature of:

20 °C