RSS-4, DRY SUBSTANCE

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18/08/2008-17/10/2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Deviations:

yes

Remarks:

Please check field "principles of method..."

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.

GLP compliance:

yes (incl. QA statement)

Remarks:

UK GLP Standards (Schedule 1, Good Laboratory Practice Regulations 1999 (SI 1999/3106 as amended by SI 2004/0994)).

Type of method:

ring method

Surface tension:

72.3 mN/m

Temp.:

21.8 °C

Conc.:

1.02 g/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	21.8	72.44	0.999
72.5	21.8	72.44	0.999
72.5	21.8	72.44	0.999
72.5	21.8	72.44	0.999
72.5	21.8	72.44	0.999
72.5	21.8	72.44	0.999
72.5	21.8	72.44	0.999
Mean Calibration Factor = 0.999

Sample solution readings

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

Time (mins)	Reading (mN/m)	Temperature (ºC)
88	72.0	21.8
113	72.5	21.8
123	72.5	21.8
134	72.5	21.8
143	72.5	21.8
153	72.5	21.8

Mean reading                    :   72.4 mN/m
Surface tension                  = reading x calibration factor
                                         = 72.4 x 0.999
                                         = 72.3 mN/m
Temperature                      :   22.0 ± 0.5ºC
pH of sample solution        :   6.5

Conclusions:

The surface tension of a 1.02 g/L solution of test material has been determined to be 72.3 mN/m at 22.0 ± 0.5 °C. The test material is considered not to be a surface-active material.

Executive summary:

The determination was carried our using a White Electrical Institute interfacial tension balance and a procedure based on the ISO 304 ring method. With the exception of the following deviation, the experimental procedure used complied with that specified in Method A.5 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

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 the surface tension that is within the required accuracy (± 0.5 mN/m); this is as a result of the reduced ring dimensions.

The deviation has been considered not to have affected the integrity of the study.

Under the conditions of the test the substance 1.02 g/L in water) has been determined to be 72.3 mN/m at 22.0 ± 0.5 °C. The substance is considered not to be surface-active.

Description of key information

The surface tension of a 1 g/L solution of the substance was determined to be 72.3 mN/m at 22°C. The substance is therefore not considered to be surface active.

Key value for chemical safety assessment

Surface tension:

72.3

in mN/m at 20°C and concentration in mg/L:

1 017

Additional information

The surface tension of the substance was determined using a White Electrical Institute interfacial tension balance and a procedure based on the ISO 304 ring method.