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Surface tension

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Reference
Endpoint:
surface tension
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1992-04-29 - 1992-04-29 (experimental phase)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 115 (Surface Tension of Aqueous Solutions)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: ISO Standard 304 ("Surface active agents - Determination of Surface Tension by Drawing up Liquid Films")
Deviations:
no
Principles of method if other than guideline:
As an alternative to the ring method, which has been primarily suggested by OECD TG 115 (original guideline, adopted 1981), the Wilhelmy plate method was preferred by the test lab because it allows a better assessment of the time dependence of the surface tension, if present. A comparison (contained in the study report) of the surface tension values of four calibrating liquids, measured with the equipment (of the test lab) using the Wilhelmy plate, with reference values from OECD TG 115 and ISO Standard 304 showed differences of less than 0.2 mN/m.
GLP compliance:
yes
Type of method:
plate method
Surface tension:
57.2 mN/m
Temp.:
20 °C
Conc.:
0.59 mg/L
Remarks on result:
other: experiment 1; the given concentration of the filtrated suspensions is an estimated value, based on the reported water solubility at 25°C
Surface tension:
56.8 mN/m
Temp.:
20 °C
Conc.:
0.59 mg/L
Remarks on result:
other: experiment 2; the given concentration of the filtrated suspensions is an estimated value, based on the reported water solubility at 25°C
Surface tension:
57
Temp.:
20 °C
Conc.:
0.59 mg/L
Remarks on result:
other: average of both experiments; the given concentration of the filtrated suspensions is an estimated value, based on the reported water solubility at 25°C

No time dependence of the surface tension was observed.

Remark of the registrant: The surface tension at 20 °C was measured with saturated aqueous solutions of technical grade substance (Wilhelmy plate method). These solution were prepared by shaking of 10 g/L suspensions and subsequent filtration. The corresponding concentrations have not been determined. In another report (see IUCLID section 4.8, Rodler) the solubility of pure grade substance in pure water at 25 °C was measured as 0.59 mg/L. This reported water solubility (different temperature and different purity) is taken as an approximate estimate for the concentrations used for the surface tension determinations.

For comparison: pure water has a surface tension at 20 °C of 72.75 mN/m.

Conclusions:
The study is considered to be adequate and reliable.
Executive summary:

The surface tension of a saturated aqueous solution at 20°C was determined with the Wilhemy plate method as 57 mN/m. The corresponding concentration of the substance is estimated to be approximately 0.59 mg/L.

Description of key information

Surface tension (Ryser, Wilhelmy plate method, saturated solution, 20 °C): 57 mN/m

Key value for chemical safety assessment

Surface tension:
57
in mN/m at 20°C and concentration in mg/L:
0.59

Additional information

Surface tension has been measured in one study. The result is considered to be reliable and adequate, and is carried forward for use in risk assessment, classification and labelling. The given concentration of the saturated solution is an approximate estimate, based on the reported water solubility.