Disodium 3,3'-[[6-[bis(2-hydroxyethyl)amino]-1,3,5-triazine-2,4-diyl]bis[imino(3-methoxy-4,1-phenylene)azo]]bis[benzenesulphonate]

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 July 19 to September 08, 2017

Reliability:

2 (reliable with restrictions)

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)

Qualifier:

according to guideline

Guideline:

other: OECD Test Guideline 105 (Water solubility)

Version / remarks:

1995

Qualifier:

according to guideline

Guideline:

other: EU Method A.6 (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:

log Pow

Partition coefficient:

-3.31

Temp.:

20 °C

Remarks on result:

other: estimation method (solubility ratio)

Details on results:

MAIN TEST
The partition coefficient was calculated from the solubilities in water and 1-octanol. The water solubility of the test item was determined in specific study (see IUCLID section 4.8) to be 21.03 g/l. Thus, the partition coefficient (Pow) of the test item was calculated to be 4.88 x10^-04 (log Pow = -3.31).

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 99.9 % to 102.3 %, which shows a good accuracy of the analytical method.

PRELIMINARY TEST
With the values of the water solubility determined specific test (21.03 g/l of the test item) and the estimated solubility in octanol from this preliminary test, the partition coefficient can be estimated to be below -2.3. Therefore, the log Pow was carried out by determining the solubility in 1-octanol by means of the flask method, which is also used for the determination of the water solubility.

Results of the flask method

Standard solution (nominal value [mg/l])	Measured value [mg/l]	Repeatability [%]
Ü-3 (10.22)	10.41	101.8
	10.46	102.3
Ü-2 (10.58)	10.57	99.9
	10.76	101.7

Measurement of a standard solution

Flask	1a	2a	3a	4a
measured value [mg/l]	9.05 / 9.65	10.71 / 10.66	10.62 / 10.94	-- / --
average octanol solubility [mg/l]	9.35	10.68	10.78	--
mean value of the octanol solubility [mg/l]	10.27			--
standard deviation [mg/l]	0.8			--
relative standard deviation [%]	7.77			--

Preliminary test for the water solubility

Amount of test item [mg]	Total volume of added octanol [ml]	Stirring time at RT [min]	Remark
89.41	10	30	not dissolved
	40	35	not dissolved
	90	30	not dissolved
14.28	20	35	not dissolved
	70	75	not dissolved
	120	35	not dissolved
	170	> 1080	not dissolved

Conclusions:

log Pow: -3.31 at 20 °C

Executive summary:

The partition coefficient of test item was determined by shake-flask method following the procedures outlined into the OECD guideline 107 and OECD guidline 105. The partition coefficient was calculated from the solubilities in water and 1-octanol. The water solubility of the test item was determined in specific study (see IUCLID section 4.8) to be 21.03 g/l. Thus, the partition coefficient (Pow) of the test item was calculated to be 4.88 x10^-04 (log Pow = -3.31).

Conclusion

log Pow: -3.31 at 20 °C

Description of key information

log Pow: -3.31 at 20 °C

Key value for chemical safety assessment

Log Kow (Log Pow):

-3.31

at the temperature of:

20 °C

Additional information

OECD 107 - estimation method (solubility ratio)