Sodium 2-sulphonatoethyl laurate

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

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.

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

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

Type of method:

flask method

Water solubility:

48.4 g/L

Conc. based on:

test mat.

Temp.:

20 °C

Remarks on result:

other: See 'Remarks'

Remarks:

The water solubility of the substance was determined at three different loading rates of 50 g/L, 60 g/L and 100 g/L. Under the conditions of the study, the water solubility of the substance was not dependent on loading rate. A loading level of approximately 100 g/L was considered the highest possible loading at which the test substance is suitable for use. Water solubility values of 46.6 g/L at loading rate of 50 g/L, 51.6 g/L at loading rate of 60 g/L and 47.1 g/L at loading rate of 100 g/L were obtained for the substance. Therefore, an overall water solubility of the test item, Sodium Lauroyl Isethionate, has been determined to be 48.4 g/L at 20.0 ± 0.5°C.

Details on results:

Preliminary test:
The preliminary estimate of water solubility is shown in the following table:

Sample Concentration (g/l)
1 25.0
2 8.22

Definitive test:

Loading rate 50g/l:

The mean peak areas relating to the standard solutions are shown in the following table:

Solution	Mean Area
Standard 10.0 mg/l	2.103 x 10^6
Standard 50.0 mg/l	8.717 x 10^6
Standard 100 mg/l	1.542 x 10^7
Standard 99.8 mg/l	1.521 x 10^7
Standard 250 mg/l	3.014 x 10^7
Standard 500 mg/l	4.885 x 10^7
Matrix blank	0.000

The mean peak areas relating to the sample solutions are shown in the following table:

Solution	MeanArea
Sample 1A	3.112 x 10^7
Sample 1B	2.963 x 10^7
Sample 2A	3.158 x 10^7
Sample 2B	3.175 x 10^7
Sample 3A	2.783 x 10^7
Sample 3B	2.792 x 10^7

The calibration curve from which the sample concentrations were interpolated is shown in 1.

The concentration (g/l) of the test item in the sample solutions is shown in the following table:

Sample Number	Time Shaken at ~ 30ºC (hours)	Time Equilibrated at 20ºC (hours)	Concentration (g/l)	Solution pH
1	72	24¼	47.3	7.2
2	48	24¼	49.9	7.1
3	24	24¼	42.5	7.2

Mean concentration: 46.6 g/l at 20.0 ± 0.5ºC
Range:                                   42.5 to 49.9 g/l

Loading rate 60g/l:

The mean peak areas relating to the standard solutions are shown in the following table:

Solution	Mean Area
Standard 10.0 mg/l	2.103 x 10^6
Standard 50.0 mg/l	8.717 x 10^6
Standard 100 mg/l	1.542 x 10^7
Standard 99.8 mg/l	1.521 x 10^7
Standard 250 mg/l	3.014 x 10^7
Standard 500 mg/l	4.885 x 10^7
Matrix blank	0.000

 

The mean peak areas relating to the sample solutions are shown in the following table:

Solution	MeanArea
Sample 1A	3.247 x 10^7
Sample 1B	3.292 x 10^7
Sample 2A	3.170 x 10^7
Sample 2B	3.179 x 10^7
Sample 3A	3.319 x 10^7
Sample 3B	3.264 x 10^7

The calibration curve from which the sample concentrations were interpolated is shown in Figure 2:

The concentration (g/l) of the test item in the sample solutions is shown in the following table:

Sample Number	Time Shaken at ~ 30ºC (hours)	Time Equilibrated at 20ºC (hours)	Concentration (g/l)	Solution pH
1	72	24¼	52.1	7.1
2	48	24¼	50.1	7.1
3	24	24¼	52.5	7.1

Mean concentration: 51.6 g/l at 20.0 ± 0.5ºC
Range:                                   50.1 to 52.5 g/l

Loading rate 100g/l:

The mean peak areas relating to the standard solutions are shown in the following table:

Solution	MeanArea
Standard 10.2 mg/l	2.171 x 10^6
Standard 50.8 mg/l	9.693 x 10^6
Standard 102 mg/l	1.773 x 10^7
Standard 109 mg/l	1.868 x 10^7
Standard 254 mg/l	3.563 x 10^7
Standard 508 mg/l	6.018 x 10^7
Matrix blank	0.000
Standard 10.2 mg/l	2.079 x 10^6
Standard 50.8 mg/l	9.336 x 10^6
Standard 102 mg/l	1.704 x 10^7
Standard 109 mg/l	1.864 x 10^7
Standard 254 mg/l	3.618 x 10^7
Standard 508 mg/l	5.952 x 10^7

The mean peak areas relating to the sample solutions are shown in the following table:

Solution	MeanArea
Sample 1A	4.704 x 10^7
Sample 1B	4.681 x 10^7
Sample 2A	3.478 x 10^7
Sample 2B	3.524 x 10^7
Sample 3A	3.443 x 10^7
Sample 3B	[1]

 

[1]Not enough solution after centrifugation to allow duplicate sampling.

The calibration curve from which the sample concentrations were interpolated is shown in Figure 3 attachment 1.

The concentration (g/l) of the test item in the sample solutions is shown in the following table:

Sample Number	Time Shaken at ~ 30ºC (hours)	Time Equilibrated at 20ºC (hours)	Concentration (g/l)	Solution pH
1	72	24	69.6[1]	[2]
2	48	24	47.6	†
3	24	24	46.6	†

Mean concentration: 47.1 g/l at 20.0 ± 0.5ºC
Range:                                   46.6 to 47.6 g/l

[1]Not used in calculation of overall mean as inconsistent.

[2]Not enough solution to allow accurate assessment.

Conclusions:

The water solubility of the test item, Sodium Lauroyl Isethionate, has been determined to be 46.6 g/l of solution at 20.0 ± 0.5°C when loaded at approximately 50 g/l.

The water solubility of the test item, Sodium Lauroyl Isethionate, has been determined to be 51.6 g/l of solution at 20.0 ± 0.5°C when loaded at approximately 60 g/l.

The water solubility of the test item, Sodium Lauroyl Isethionate, has been determined to be 47.1 g/l of solution at 20.0 ± 0.5°C when loaded at approximately 100 g/l.

The overall water solubility of the test item, Sodium Lauroyl Isethionate, has been determined to be 48.4 g/l at 20.0 ± 0.5°C.

Executive summary:

The water solubility of the test item, Sodium Lauroyl Isethionate, at three different loading rates was determined using the flask method, Method A6 Water Solubility ofCommissionRegulation (EC) No 440/2008 of 30 May 2008.

The loading rates and concentrations are shown in the following table:

Approximate Loading Level (g/l)	Water Solubility at 20.0 ± 0.5°C (g/l)
50	46.6
60	51.6
100	47.1

It was evident from the results obtained that the water solubility was not affected by loading rate. A loading level of approximately 100 g/l was considered to the highest possible loading level concentration. Preparing at greater concentrations would yield a sample which would be unsuitable for use as it would be unfilterable and non-centrifugable. It was therefore not possible to prepare samples at five times the saturation level as recommended in the guideline.

The overall water solubility of the test item, Sodium Lauroyl Isethionate, has been determined to be 48.4 g/l at 20.0 ± 0.5°C.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08 July 2013 - 06 September 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed in accordance with the EC A.6 and OECD 105 guidelines and complied with the principles of GLP.

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

(2008)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

(1995)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7840 (Water Solubility)

Version / remarks:

(1998)

Deviations:

no

GLP compliance:

yes

Type of method:

flask method

Water solubility:

1.29 g/L

Temp.:

20 °C

pH:

ca. 5.6 - ca. 6

Remarks on result:

other: Mean of the analysed concentrations at t=24, 48 and 72 h.

Details on results:

The maximum difference (MD) of the concentrations determined in the 24, 48 and 72 hour test samples was 18%. Though the 24 and 72 hour test results were within 15% agreement, it was decided to calculate the water solubility of the test substance as the mean value of all the analysed concentrations because the overall variation was small and each individual result was close to the mean calculated water solubility.

A small peak was detected in the chromatogram of the pretreated sample from the blank water mixture. This response was equal to the response in the analytical blank and was therefore considered not to derive from the water solubility study.

Water solubility results

 

Stirring time [hours]	Analysed concentration [g/l]	Mean [g/l]	MD [%]	pH
24	1.30	1.29	18	5.6
48	1.17			5.9
72	1.40			6.0

Conclusions:

The water solubility of the substance at 20°C has been determined as 1.29 g/L using the flask method (GLP-compliant study in accordance with EC A.6, OECD 105 and OPPTS 830.7840). The pH of the saturated solution was 5.6-6.0.

Description of key information

The water solubility of the test item, Sodium Lauroyl Isethionate, has been determined to be 46.6 g/l of solution at 20.0 ± 0.5°C when loaded at approximately 50 g/l.  The water solubility of the substance at 20°C has been determined as 1.29 g/L using the flask method (GLP-compliant study in accordance with EC A.6, OECD 105 and OPPTS 830.7840). The pH of the saturated solution was 5.6-6.0.

Key value for chemical safety assessment

Water solubility:

1.29 g/L

at the temperature of:

20 °C