Essential oil of Boswellia carterii (Burseraceae) obtained from gum by distillation

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 12 to 16 February 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The study was conducted according to an internationally recognised method, and under GLP. The test substance is adequately characterised. Therefore full validation applies.

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

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected on 13 and 14 October 2014 / signed on 08 April 2015

Type of method:

plate method

Key result

Surface tension:

62.13 mN/m

Temp.:

19.7 °C

Conc.:

50.03 mg/L

Remarks on result:

other: The concentration of the test item in the 90 % saturated test solution was determined to be 50.03 mg/L (based on analysis of dissolved organic carbon in the test solution).

Findings MainTest

The test item solution was held at constant temperature (20.0 ± 0.5 °C). 64 minutes after conclusion of the first measurement series, a second measurement series was performed for verification purposes.

The following values were recorded:

Table 1.-  Measured Values Test Item First Series

Measurement	Time	Mass	Surface Tension	Temperature
No	s	g	mN/m	°C
1	3.0	0.2541	61.99	19.7
2	5.9	0.2550	62.21	19.7
3	8.9	0.2548	62.16	19.7
4	11.9	0.2548	62.16	19.7
5	14.9	0.2546	62.11	19.7
6	17.9	0.2547	62.13	19.7
7	20.9	0.2548	62.16	19.7
8	23.9	0.2548	62.16	19.7
9	26.9	0.2548	62.16	19.7
10	29.9	0.2544	62.06	19.7
Mean			62.13
Standard Deviation			0.06

Table 2.-Measured Values Test Item Second Series

Measurement	Time	Mass	Surface Tension	Temperature
No	s	g	mN/m	°C
1	2.9	0.2498	60.94	19.7
2	5.9	0.2531	61.74	19.7
3	8.9	0.2532	61.77	19.7
4	11.9	0.2532	61.77	19.7
5	14.9	0.2530	61.72	19.7
6	17.9	0.2530	61.72	19.7
7	20.9	0.2528	61.67	19.7
8	23.9	0.2529	61.69	19.7
9	26.9	0.2529	61.69	19.7
10	29.9	0.2530	61.72	19.7
Mean			61.64
Standard Deviation			0.25

After the first and the second measurement series, the difference between mean values was less than 5%. Therefore no additional measurement series was required.

 Analytical Determinations

TOC analysis of the filtrated test solution was performed using the carbon analyser TOC multi N/C 2100S, Analytik Jena. The test solution was measured in triplicate. The carbon analyser was calibrated with freshly prepared reference solutions containing potassium hydrogen phthalate (TC), sodium hydrogen carbonate and sodium carbonate (IC) every month. After every start, quality control samples were measured.

A value of 43.13 mg org. carbon/L was obtained, and the concentration of the test item was calculated from the measured DOC and the stated carbon content. The calibration data is presented in chapter15 page16.

The carbon content in the test item had been determined under non-GLP-conditions in the laboratory Mikroanalytisches Labor Pascher (D-53424 Remagen) with 86.20 %w/w.

The concentration was therefore determined with 50.03 mg test item/L.

Result Test Item

During the specified period of time, no relevant changes in the surface tension were detected. Values ranging from 60.94 mN/m to 62.21 mN/m were recorded showing no relevant variations. The values of the single determinations show no significant difference (less than 5 % between mean values of the two measurement series)

As the determined surface tension of the test item was higher than 60 mN/m, the test item can be classified as not surface active.

Validity

Literature value for the surface tension of H₂O at 19.0 °C: 72.90 mN/m (taken from Vargaftik et al., “International Tables of the Surface Tension of Water”, J. Phys. Chem. Ref. Data 12, 817, 1983).

The surface tension of the negative control was determined with 73.00 mN/m at 19.2 °C, therefore showing a difference of 0.14% from the stated literature value. The difference lies within the accepted range of 1% deviation from literature value.

Conclusions:

The surface tension of an aqueous solution of the test item was determined as 62.13 ± 0.06 mN/m at 19.7 °C. As all measured values were above 60 mN/m, it is classified as not surface active.

Executive summary:

The surface tension of test item was determined according to EU method A.5 and OECD 115.

The concentration of the test item in the 90 % saturated test solution was determined to be 50.03 mg/L (based on analysis of dissolved organic carbon in the test solution). The saturated solution was obtained from an aqueous solution prepared with 1 g/L of test item slow-stirred for 72 h.

The surface tension of the negative control lay within the accepted range.

The surface tension of an aqueous solution of the test item was determined as 62.13 ± 0.06 mN/m at 19.7 °C. One measurement series was performed for verification (after 64 minutes). No significant changes and thus no significant dependence on time were observed. As all measured values were higher than 60 mN/m, the test item is classified as not surface active.

Description of key information

Surface tension = 62.13 mN/m, at 90% saturation expected (50.03 mg/L)
Since the measured result is higher than the threshold value of 60 mN/m, according to EU A5 criteria, the substance is considered as not surface-active under the experimental conditions.

Key value for chemical safety assessment

Surface tension:

62.13

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

50.03

Additional information

A fully reliable experimental study, conducted according to a recognized OECD/EU/ISO method and under GLP, is available. It is considered as a key study, and the result is retained as key value.

The concentration of the test item in the 90 % saturated test solution was determined to be 50.03 mg/L (based on analysis of dissolved organic carbon in the test solution).