Fatty acids, tall-oil, reaction products with boric acid (H3BO3) and diethanolamine

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10-01-2012 to 23-04-22012

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:

EU Method A.5 (Surface Tension)

Deviations:

no

GLP compliance:

yes

Type of method:

ring method

Surface tension:

ca. 50 mN/m

Temp.:

21 °C

Conc.:

0.05 g/L

During the initial nine measurements for Sample A they gradually increased from 51 mN/m to 53.5 mN/m but with the penultimate measurement being only 50.0 mN/m. It was decided to store the samples and continue the measurements on another day. On continuation the measurements for Sample A started at only 45.0 mN/m but again the eight measurements steadily increased to 53.0 mN/m but with no plateau. Sample B, after being stored over the weekend, was then tested with seven measurements starting at 44.0 mN/m and also gradually increased to 50.5 mN/m. It was then considered that the surface tension varied depending on whether the sample had been left to equilibrate for a substantial aount of time or was tested soon after a previous reading. It could be that there is excess test item which interferes with the meaurement. Especially if it builds up at the sample surface so that the platinum ring is in contact with test item not just the aqueous solution therefore giving a false low result. Throughout the sample measurements, calibration measurements of glass double distilled water were taken and these were all within the calibration range. Testing was performed between 21.4 °C and 22.2 °C.

Conclusions:

Overall, it was considered that the test was not applicable to measuring a definitive surface tension result for the test item in water. It is probable that the test item and/or its degradation products have a significant effect on the surface tension of water and so would be considered surface active. Although, if all the excess test item could be removed and as expected water solubility is extremely low, it may not have a significant effect on the surface tension of water.

Executive summary:

Test Guidance

OECD Guideline No. 115 and EU Method A.5

Method and materials

Two samples were prepared by shaking approximately 0.1g of test item with 500 m of glass double distilled water for 1 hours and equilibrating to 20°C for approximately ½ hour. The solution was filtered twice through 0.2 µm nylon filters. Although the filtrate looked clear and free from excess test item with the naked eye, a Tyndall beam effect was clearly seen when a beam of light was shone through it. Although the samples for the surface tension test should contain no excess test item, it was not possible to remove it all. The filtrates were diluted to 90% with glass double distilled water and the surface tension measurements made.

The determination was carried out usinfg a White Electrical Institute Co. Ltd. torsion balance for surface and interfacial tension measurements and a procedure based on the ISO 304 ring method. Testing was performed between 21.4°C and 22.2°C.

Results

During the initial nine measurements for Sample A they gradually increased from 51 mN/m to 53.5 mN/m but with the penultimate measurement being only 50.0 mN/m. It was decided to store the samples and continue the measurements on another day. On continuation the measurements for Sample A started at only 45.0 mN/m but again the eight measurements steadily increased to 53.0 mN/m but with no plateau. Sample B, after being stored over the weekend, was then tested with seven measurements starting at 44.0 mN/m and also gradually increased to 50.5 mN/m. It was then considered that the surface tension varied depending on whether the sample had been left to equilibrate for a substantial aount of time or was tested soon after a previous reading. It could be that there is excess test item which interferes with the meaurement. Especially if it builds up at the sample surface so that the platinum ring is in contact with test item not just the aqueous solution therefore giving a false low result. Throughout the sample measurements, calibration measurements of glass double distilled water were taken and these were all within the calibration range.

Conclusions

Overall, it was considered that the test was not applicable to measuring a definitive surface tension result for the test item in water. It is probable that the test item and/or its degradation products have a significant effect on the surface tension of water and so would be considered surface active. Although, if all the excess test item could be removed and as expected water solubility is extremely low, it may not have a significant effect on the surface tension of water.

Description of key information

Surface activity could not be determined (OECD 115 and EU Method A.5).

Additional information

It was considered that the test was not applicable to measuring a definitive surface tension result for the test item in water. It is probable that the test item and/or its degradation products have a significant effect on the surface tension of water and so would be considered surface active. Although, if all the excess test item could be removed and as expected water solubility is extremely low, it may not have a significant effect on the surface tension of water.