3-[(3-sulfanylbutanoyl)oxy]-2,2-bis{[(3-sulfanylbutanoyl)oxy]methyl}propyl 3-sulfanylbutanoate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Between 07 January 2009 and 17 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 the relevant results.

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of inspection: 19th August 2008 Date of signature: 4th March 2009

Type of method:

flask method

Key result

Water solubility:

0.001 g/L

Temp.:

20 °C

pH:

5.5 - 6.9

Remarks on result:

other: Component B (main constituent; PEMB)

Key result

Water solubility:

0.034 g/L

Temp.:

20 °C

pH:

5.5 - 6.9

Remarks on result:

other: Component A (minor constituent)

Details on results:

Preliminary test
The preliminary estimate of water solubility was for 1.43 x 10-2 g/L for Component A and 2.76 x 10-3 g/l for Component B.

 Definitive test

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

Component A:

Solution	Mean Peak Area
Standard 53.0 mg/L	621.161
Standard 56.5 mg/l	623.677
Matrix Blank	0
Sample 1A	849.078
Sample 1B	848.593
Sample 2A	1.058 x 10^3
Sample 2B	1.061 x 10^3
Sample 3A	1.237 x 10^3
Sample 3B	1.229 x 10^3
Standard 65.5 mg/L	556.123
Standard 67.0 mg/l	540.009
Matrix Blank	0
Sample 4A	958.497
Sample 4B	956.012
Sample 5A	948.516
Sample 5B	949.105
Sample 6A	1.009 x 10^3
Sample 6B	1.004 x 10^3

Component B

Solution	Mean Peak Area[1]
Standard 5.30 mg/L	801.302
Standard 5.65 mg/L	649.576
Matrix Blank	46.083
Sample 1A	118.167
Sample 1B	145.403
Sample 2A	176.376
Sample 2B	173.956
Sample 3A	223.003
Sample 3B	132.230
Standard 65.5 mg/L	376.650
Standard 67.0 mg/L	371.706
Matrix Blank	0
Sample 4A	26.315
Sample 4B	25.479
Sample 5A	25.098
Sample 5B	22.892
Sample 6A	27.145
Sample 6B	27.307

[1]Standard and sample mean peak areas have been corrected for the mean peak area of the matrix blank.

The concentration (g/l) of test material 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) Component A	Concentration (g/l) Component B	Solution pH
1	24	24	2.13 x 10^-2	1.64 x 10^-3 †	6.3
2	48	24	2.66 x 10^-2	2.19 x 10^-3†	6.7
3	72	24	3.10 x 10^-2	2.22 x 10^-3†	6.9
4	96	24	3.31 x 10^-2	7.61 x 10^-4	5.5
5	120	24	3.28 x 10^-2	7.05 x 10^-4	5.6
6	144	24	3.49 x 10^-2	8.00 x 10^-4	6.1

† Data not used included in the mean concentration

Component	Mean Concentration (g/L) at 20.0 ± 0.5 ºC	Range (g/L)
A	3.36 x 10^-2	3.28 x 10^-2to 3.49 x 10^-2
B	7.55 x 10^-4	7.05 x 10^-4to 8.00 x 10^-4

 Discussion:

The concentration of Component A was considered to have reached a plateau after 96 hours. Therefore the data from 96, 120 and 144 hours was used to calculate the mean water solubility concentration for Component A of the test material.

Component B results from the 24, 48 and 72 hour samples were considered to be artificially elevated possibly due to an interfering peak in the chromatography (see chromatogram below). The chromatography for the latter time-points was noted to be free from interference and reproducibility of the data was significantly improved. It was considered appropriate to use only the data from 96, 120 and 144 hour time-points tor calculation of the water solubility of Component B of the test material It is evident from the structural information that although there are functional groups present that may be prone to hydrolysis. However, the calculated estimate of hydrolysis at pH 7 gives half-lives of approximately 13 and 10 years for Components A and B respectively (HYDROWIN v1.67, EPISuite version 3.11, copyright 2000 - 2007 US Environment Protection Agency). Data relating to the pH of the test material in water indicates that negligible hydrolysis of the sample solution occurred during the course of the water solubility test.

Conclusions:

Interpretation of results (migrated information): slightly soluble (0.1-100 mg/L) both the minor and main constituents fall into this category
The water solubility of the test material has been determined using the flask method and the results are shown in the following table:

Component Concentration (g/l) at 20.0 ± 0.5 ºC
A (minor) 3.36 x 10-2
B (main) 7.55 x 10-4

Executive summary:

Water Solubility:  The water solubility the test material has been determined using the flask method, Method A.6 Water Solubility of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 105 of the OECD Guidelines for Testing of Chemicals, 27 July 1995. The results are shown in the following table:

Component	Concentration (g/l) at 20.0 ± 0.5ºC
A (minor)	3.36 x 10^-2
B (main, PEMB)	7.55 x 10^-4

Description of key information

The water solubility of the substance was determined as 0.755 mg/L (main constituent) according to OECD Guideline 105 using the flask method.

Key value for chemical safety assessment

Water solubility:

0.755 mg/L

at the temperature of:

20 °C

Additional information

Samples stirring times were prolonged to 96, 120 and 144 hours, because analytical results indicated that the maximum solubility (plateau) had not been reached after 72 hours of stirring. Additionally, the solubility of the main constituent was considered to be overestimated in the 24 -, 48 - and 72 hours samples due to interferences in the chromatography.

It was concluded that the water solubility of the minor constituent PE3MB is 33.6 mg/L at 20 °C (component A) whereas the water solubility of the main constituent PEMB was determined to be 0.755 mg/L at 20 °C (component B). Since the latter constituent is of main interest, the key value for the water solubility of PEMB will be assigned as 0.755 mg/L.