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

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

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.5 (Surface Tension)

Deviations:

yes

Remarks:

The surface tension result was not corrected using the Harkins-Jordan correction table

Qualifier:

according to guideline

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

Deviations:

yes

Remarks:

The surface tension result was not corrected using the Harkins-Jordan correction table

Qualifier:

according to guideline

Guideline:

other: ISO 304 ring method

Deviations:

yes

Remarks:

The surface tension result was not corrected using the Harkins-Jordan correction table

Principles of method if other than guideline:

The surface tension result was not corrected using the Harkins-Jordan correction table as the correction is not applicable to the apparatus used. Once calibrated, the balance and ring assembly used in this test give a direct reading for surface tension that is within the required accuracy (± 0.5 mN/m); this is as a result of the reduced ring dimensions.This deviation has been considered not to have affected the integrity of the study.

GLP compliance:

yes (incl. QA statement)

Remarks:

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

Type of method:

ring method

Key result

Surface tension:

60.1 mN/m

Temp.:

22 °C

Conc.:

0.033 g/L

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

Component A:

Solution	Mean Peak Area
Standard 108 mg/L	950.588
Standard 101mg/L	830.602
Matrix blank	0
Sample A	975.161
Sample B	987.493
Mean sample solution concentration = 3.30 x 10^-2g/L

Component B :

Solution	Mean Peak Area
Standard 1.08 mg/L	68.908
Standard 1.01mg/L	69.817
Matrix blank	0
Sample A	24.667
Sample B	26.729
Mean sample solution concentration = 6.42 x 10^-4g/L

Calibration factor (f):

The readings, temperatures and the corresponding calibration factors for glass double-distilled water are shown in the following table:

Reading (mN/m)	Temperature (ºC)	Literature Value (mN/m)	Calibration Factor
72.5	22.0	72.41	0.999
72.0	22.0	72.41	1.006
72.5	22.0	72.41	0.999
72.0	22.0	72.41	1.006
72.0	22.0	72.41	1.006
72.5	22.0	72.41	0.999
72.0	22.0	72.41	1.006
72.0	22.0	72.41	1.006
72.0	22.0	72.41	1.006
72.0	22.0	72.41	1.006
Mean Calibration Factor (mean of last eight) = 1.004

The readings, times and temperatures for the sample solution are shown in the following table:

Time (mins)	Reading (mN/m)	Temperature (ºC)
100	58.5	22.0
110	59.0	22.0
120	59.5	22.0
128	60.0	22.0
137	60.0	22.0
145	59.5	22.0
153	60.0	22.0
162	60.0	22.0
170	60.0	22.0

Mean reading (mean of last seven):          59.9 mN/m
Surface tension:                                          = reading x calibration factor
                                                                     = 59.9 x 1.004
                                                                     = 60.1 mN/m
Temperature:                                                22.0 ± 0.5 ºC
pH of sample solution:                                 7.2

Discussion:

Substances showing a surface tension lower than 60 mN/m should be regarded as being surface‑active. It is evident from the structural information that 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©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 surface tension test.

Conclusions:

The surface tension of an aqueous solution of test material (3.30 x 10-2 g/L of Component A, 6.42 x 10-4 g/L of Component B) has been determined to be 60.1 mN/m at 22.0 ± 0.5 °C, using similar procedure as applied in the OECD ring method. The test material is considered not to be a surface-active material.

Executive summary:

Surface Tension: The surface tension of the test material has been determined to be 60.1 mN/m (3.30 x 10-2g/L of Component A, 6.42 x 10-4g/L of Component B) at 22.0 ± 0.5 °C, using a ring method based on ISO 304, Method A.5 Surface Tension of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 115 of the OECD Guidelines for Testing of Chemicals, 27 July 1995. The test material is considered not to be a surface-active material.

Description of key information

The surface tension of the substance was determined as 60.1 mN/m at 22 °C according to OECD Guideline 115 using a procedure based on the ISO 304 ring method (similar procedure as applied in the OECD harmonised ring method, but no Harkins-Jordan correction due to different ring dimensions). 

Key value for chemical safety assessment

Surface tension:

60.1

Additional information

The surface tension of the substance was determined in a 90% (v/v) solution of an approximately 1 g/L (saturated) aqueous solution. Since the apparatus used (reduced ring dimensions as compared to OECD harmonised ring method) gives a direct reading for surface tenison within the required accuracy (+/- 0.5 mN/m), the commonly used Hawkins-Jordan correction table was not applied to the data.

In result, the surface tenison of the test solution was determined as 60.1 mN/m at 22.0 ± 0.5 °C.

In view of the generally acknowledged trend, that surface tension decreases with the increase of temperature, the obtained value at 22°C could be considered as worst case, i.e. at 20°C the surface tension of the substance is expected to be slightly higher. Therefore, the key value for chemical safety assessment will be set at 60.1 mN/m. The substance is considered to be not surface active.