Magnesium metaborate

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016-07-29 - 2017-09-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Version / remarks:

30 May 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

Version / remarks:

27 July 1995

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Type of method:

ring method

Key result

Surface tension:

<= 67 mN/m

Temp.:

21 °C

Conc.:

5.5 g/L

Remarks on result:

other: see 'Remarks'

Remarks:

loading rate of 5.5 g/L (1.1 g/L active)

The readings, times and temperatures for the sample solutions are shown in the following tables:

Sample 1:

Age of Solution (min)	Reading (mN/m)	Temperature (°C)
70	72.0	21.2
80	72.0	21.2
93	72.0	21.2
102	72.0	21.2
112	72.0	21.2

Sample 2:

Age of Solution (min)	Reading (mN/m)	Temperature (°C)
200	65.0	21.2
210	65.5	21.2
219	65.5	21.2
228	66.0	21.2
238	67.0	21.2
249	67.0	21.2
259	67.0	21.2
268	67.0	21.2
276	67.0	21.2

Mean Sample 1 result: 72.0 mN/m

Mean Sample 2 result*: 76.0 mN/m

Overall result: ≤ 67.0 mN/m

Overall temperature: 21.0 ± 0.5 ºC

pH of Sample 1: 7.0

pH of Sample 2: 7.6

Discussion

The samples were prepared at a loading rate of 5.5 g/L rather than the specified test limit of 1 g/L. This was done so that the active ingredient concentration was approximately 1 g/L based on values supplied by the Sponsor and to act as a worst case scenario.

Sample 2 had a significantly lower surface tension than Sample 1. It was considered that some of the excess test item that was floating on the surface may have been transferred during sampling. Even so, the result was not low enough to consider the test item surface active. According to criteria stated in EC Method A.5, substances showing a surface tension lower than 60 mN/m under the conditions of this method should be regarded as being surface active. Considering the composition of the active ingredient, this would not have lowered the surface tension as seen in Sample 2.

Additionally, to act as a comparison, the surface tension of duplicate samples of the mineral oil prepared at 2.9 g/L was measured. The concentration of these samples was to reflect the approximate concentration the mineral oil contributed to the test item samples. The result for both of these samples was 72.5 mN/m. This showed the oil itself was not surface active.

Conclusions:

The surface tension of a 90 % saturated solution from a loading rate of 5.5 g/L (1.1 g/L active) has been determined to be ≤ 67.0 mN/m at 21.0 ± 0.5 °C. The test item was considered to be not surface-active.

Executive summary:

Less than or equal to 67.0 mN/m at 21.0 ± 0.5 °C (90 % saturated solution from a loading rate of 5.5 g/L (1.1 g/L active)), using a ring method, designed to be compatible with Method A5 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 item was considered to be not surface-active.

Description of key information

Less than or equal to 67.0 mN/m at 21.0 ± 0.5 °C (90 % saturated solution from a loading rate of 5.5 g/L (1.1 g/L active)), using a ring method, designed to be compatible with Method A5 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 item was considered to be not surface-active.

Key value for chemical safety assessment

Surface tension:

67

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

5 500

Additional information

The samples were prepared at a loading rate of 5.5 g/L rather than the specified test limit of 1 g/L. This was done so that the active ingredient concentration was approximately 1 g/L based on values supplied by the Sponsor and to act as a worst case scenario.

The surface tension of a 90 % saturated solution from a loading rate of 5.5 g/L (1.1 g/L active) has been determined to be ≤ 67.0 mN/m at 21.0 ± 0.5 °C. The test item was considered to be not surface-active.