Melaleuca alternifolia, ext.

Surface tension

Administrative data

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

Deviations:

no

GLP compliance:

yes

Type of method:

OECD harmonised ring method

Test material

Test material information

Constituent 1

Reference substance name:

Melaleuca alternifolia, ext.

EC Number:

285-377-1

EC Name:

Melaleuca alternifolia, ext.

Cas Number:

85085-48-9

Molecular formula:

Not applicable (a generic molecular formula cannot be provided for this specific UVCB substance).

IUPAC Name:

Essential oil of melaleuca alternifolia

Test material form:

liquid

Specific details on test material used for the study:

- Purity: 100%
- Lot (batch) No.: 1215
- Expiration date of the lot: 30 March 2009
- Storage condition of test material: Room temperature, protected from light.

Results and discussion

Surface tension

Surface tension 1

Surface tension:

51 mN/m

Temp.:

20 °C

Conc.:

90 other: % saturated

Surface tension 2

Surface tension:

55 mN/m

Temp.:

20 °C

Conc.:

1 g/L

Any other information on results incl. tables

Values obtained using the 90% saturated aqueous solution are displayed in Table 1 below. Initial values for the surface tension were obtained as soon as possible after the transfer of the aqueous solution to the measurement vessel.

Table 1. 90% saturated solution.

Time (minutes)	Surface tension (mN/m)
	Measured		Calibration corrected
	A	B	A	B
0	52.5	53.0	53.0	53.5
5	53.0	52.5	53.5	53.0
10	53.0	53.0	53.5	53.5
15	53.0	53.0	53.5	53.5
20	53.0	53.0	53.5	53.5
25	53.5	53.0	54.0	53.5
30	53.0	53.0	53.5	53.5

From the results there was no apparent time dependence of surface tension after transfer to the measuring vessel.

Overall mean calibration corrected surface tension = 53.5 mN/m

Harkins-Jordan corrected value = 51.0 mN/m

Values obtained using the 1 g/l solution are displayed in Table 2 below. Initial values for the surface tension were obtained as soon as possible after the transfer of the aqueous solution to the measurement vessel.

Table 2. 1 g/l solution.

Time (minutes)	Surface tension (mN/m)
	Measured		Calibration corrected
	A	B	A	B
0	56.5	57.0	57.0	57.5
5	56.5	57.0	57.0	57.5
10	56.5	57.5	57.0	58.0
15	56.5	57.0	57.0	57.5
20	56.5	57.5	57.0	58.0
25	56.5	57.5	57.0	58.0
30	56.5	57.5	57.0	58.0

From the results there was no apparent time dependence of surface tension after transfer to the measuring vessel.

Overall mean calibration corrected surface tension = 57.0 mN/m

Harkins-Jordan corrected value = 55.0 mN/m

Applicant's summary and conclusion

Conclusions:

The surface tension of a 90% saturated solution of Tea Tree Oil was found to be 51.0 mN/m, and the surface tension of a 1 g/l solution of Tea Tree Oil was found to be 55.0 mN/m. As the results are less than 60 mN/m, Tea Tree Oil was considered to be surface active.

Executive summary:

A GLP-compliant study was carried out to determine the surface tension of Tea Tree Oil. The study followed the requirements of EEC method A5 and OECD method 115 without significant deviation.

The surface tension of a 90% saturated solution of Tea Tree Oil was found to be 51.0 mN/m, and the surface tension of a 1 g/l solution of Tea Tree Oil was found to be 55.0 mN/m. As the results are less than 60 mN/m, Tea Tree Oil was considered to be surface active.