Fatty acids, C12-18 and C18-unsatd., 2-sulfoethyl esters, sodium salts

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

between 10 February 2009 and 02 April 2009.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of inspection: 19/08/08 Date of Signature: 04/03/09

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Test material

Reference

Name:

Unnamed

Type:

Constituent

Study design

Analytical method:

high-performance liquid chromatography

Results and discussion

Partition coefficient

Partition coefficient 1

Type:

Pow

Partition coefficient:

0.028

Temp.:

22.1 °C

pH:

>= 7.3 - <= 7.5

Partition coefficient 2

Type:

log Pow

Partition coefficient:

-1.56

Temp.:

22.1 °C

pH:

>= 7.3 - <= 7.5

Details on results:

Preliminary estimate:
Approximate solubility in n-octanol: <0.124 g/l
Approximate solubility in water: >19.0 g/l
Approximate Pow: <6.51 x 10-3
Log10 Pow: <-2.19

Any other information on results incl. tables

 Definitive test:

The mean peak areas obtained for the standard, stock and sample solutions are shown in the following two tables:

Organic Phase

Solution	Mean Area
Standard 10.0 mg/l	1.302 x 10^6
Standard 10.2 mg/l	1.376 x 10^6
Organic phase matrix blank	0.000
Sample 1	4.949 x 10^6
Sample 2	4.750 x 10^6
Sample 4	4.492 x 10^6
Sample 5	4.815 x 10^6
Sample 6	4.814 x 10^6

Aqueous Phase

Solution	Mean Area
Standard 251 mg/l	3.263 x 10^7
Standard 257 mg/l	3.404 x 10^7
Aqueous phase matrix blank	0.000
Sample 1	3.405 x 10^7
Sample 2	3.408 x 10^7
Sample 4	3.299 x 10^7
Sample 5	3.432 x 10^7
Sample 6	3.404 x 10^7
Stock solution A	3.492 x 10^7
Stock solution B	3.439 x 10^7

The total weights (mg) and analysed concentration (mg/l) of the respective phases are shown in the following table:

Sample Number	Total Weight (mg)*	Organic Phase		Aqueous Phase
		Analysed Concentration (mg/l)	Weight (mg)†	Analysed Concentration (mg/l)	Weight (mg)†	pH
1	87.2	74.7	2.46	2.60 x 10^3	85.6	7.3
2	92.4	71.7	2.51	2.60 x 10^3	90.9	7.3
4	68.7	67.8	3.52	2.51 x 10^3	65.4	7.5
5	116	72.6	1.60	2.62 x 10^3	115	7.4
6	137	72.6	1.89	2.59 x 10^3	135	7.3

pH of n-octanol saturated water:    7.3
pH of stock solution:            7.3
Temperature:                         22.1 ± 0.5°C

*From analysis of the stock solution

†From analysis of the respective phase

The partition coefficient determined for each sample is shown in the following table:

Sample Number	Organic/Aqueous Volume Ratio	Partition Coefficient	Log10Pow	Mean Partition Coefficient
1	1:1	2.88 x 10^-2	-1.54	2.82 x 10^-2
2		2.76 x 10^-2	-1.56
4	2:1	2.70 x 10^-2	-1.57	2.70 x 10^-2
5	1:2	2.78 x 10^-2	-1.56	2.79 x 10^-2
6		2.80 x 10^-2	-1.55

Mean P_ow : 2.78 x 10^-2        log₁₀P_ow: -1.56        P_owstandard deviation : 6.61 x 10^-4

Validation:

Linearities of the detector response with respect to concentration were assessed over the nominal concentration ranges of 0 to 100 mg/l for the organic phase and 0 to 500 mg/l for the aqueous phase. These were satisfactory with first order correlation coefficients of 1.000 and 0.998 obtained for the organic and aqueous phases respectively.

Discussion:

Substances having a log₁₀P_ow of greater than 3 are regarded as having the potential to bioaccumulate in the environment.

Testing was performed without any pH adjustment to the aqueous phase. Testing by the flask method at neutral pH is the preferred choice for test items that are salts. The pH of the unadjusted n-octanol saturated water and stock solutions were approximately pH 7.

Although sample 3 was abandoned during testing, it was not considered appropriate to repeat the test using a single flask at the required ratio. Results obtained in the definitive test showed consistency between all 5 samples and as such, additional testing would be anticipated to yield no further useful information.

Applicant's summary and conclusion

Conclusions:

The partition coefficient of the test item, Sodium Octanoyl Isethionate, has been determined to be 2.78 x 10-2, log10 Pow, -1.56.

Executive summary:

Partition Coefficient:

The partition coefficient of the Sodium Octanoyl Isethionate test item, Sample Number S2952201 has been determined to be 2.78 x 10^-2at 22.1 ± 0.5°C, log₁₀P_ow-1.56, using the shake-flaskthod, Method A8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008.