Poly(oxy-1,2-ethanediyl), .alpha.-sulfo-.omega.-hydroxy-, C10-12-alkyl ethers, 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:

25 - 31 Jul 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)

GLP compliance:

no

Type of method:

other: slow stirring

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

0.675

Temp.:

25 °C

pH:

4 - 4.02

Remarks on result:

other: RSD = 0.4 %

Details on results:

See "Any other information on results incl. tables"

Study results:

The concentration of the test item in the water and 1 -octanol phase was determined after 48, 50, 52 and 54 hours, ensuring that an equilibrium concentration was established in both phases. At each test time, three different test solutions were analyzed. The concentrations of the test item in the different test solutions are listed below:

Test solution	Weighed sample, mg	Volume 1-octanol, mL
1	1.154	40 (32.8 g)
2	1.152	40 (32.8 g)
3	1.158	40 (32.8 g)

Measured concentrations of the test item in the 1 -octanol and buffer solution phases of the three different test solutions at 4 different times are summarized in the following 2 tables.

Time, h	Test solution 1, test item in mg/g 1-octanol	Test solution 2, test item in mg/g 1-octanol	Test solution 3, test item in mg/g 1-octanol
48	6.223	6.188	6.245
50	6.222	6.198	6.282
52	6.251	6.239	6.234
54	6.178	6.212	6.244
Mean	6.219	6.209	6.251

Time, h	Test solution 1, test item in mg/g buffer solution	Test solution 2, test item in mg/g buffer solution	Test solution 3, test item in mg/g buffer solution
48	1.305	1.307	1.334
50	1.311	1.307	1.334
52	1.310	1.304	1.335
54	1.311	1.311	1.320
Mean	1.309	1.307	1.331

Equilibrium for all test solutions was established. The mass balance could be calculated on the basis of the measured concentrations of the test item (found value) and the corrected real sample weights of test item in 40 mL 1-octanol and 700 mL buffer solution after 54 hours.

	Test solution 1	Test solution 2	Test solution 3
Weighed sample, mg	1115	1113	1119
Found value, mg in 40 mL 1-octanol	199.2	200.3	201.4
Found value, mg in 700 mL buffer solution	915.6	916.1	925.8
Recovery, %	100.0	100.3	100.7

The calculated value considers the real sample weight and the three time points of measurement before the 54 hours measurement. The real sample weight has to be corrected for the amounts of test item that has been removed from the octanol and aqueous phases for measurement.

Subsequently, the ratios of concentrations and their logarithms were calculated.

Time, h	Test solution 1		Test solution 2		Test solution 3
	co/cw	log (co/cw)	co/cw	log (co/cw)	co/cw	log (co/cw)
48	4.768	0.678	4.734	0.675	4.681	0.670
50	4.747	0.676	4.743	0.676	4.710	0.673
52	4.773	0.679	4.786	0.680	4.670	0.669
54	4.711	0.673	4.737	0.675	4.729	0.675

The resulting mean values for the different test solutions are listed below.

Test solution	Mean value co/cw	Standard deviation	Mean value log (co/cw)	Standard deviation
1	4.750	0.028	0.677	0.00460
2	4.750	0.024	0.677	0.00408
3	4.697	0.027	0.672	0.00709
mean	4.732		0.675
RSD	0.64%		0.41%

Description of key information

log Pow  = 0.675 at 25 °C, pH = 4.00 - 4.02

Key value for chemical safety assessment

Log Kow (Log Pow):

0.675

at the temperature of:

25 °C

Additional information

The partition coefficient of the substance was determined using the slow stirring method according to OECD 123.