Juniper, Juniperus oxycedrus, ext.

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

January 15-18, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to an internationally recognised method, and under GLP. No deviation was reported. The substance is considered to be adequately characterised with its purity. 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:

55.34 mN/m

Temp.:

19.7 °C

Conc.:

199.76 mg/L

Remarks on result:

other:

Remarks:

The concentration of the test item in the 90 % saturated test solution was determined to be 199.76 mg/L (based on analysis of dissolved organic carbon in the test solution).

Findings - Main Test

The test item solution was held at constant temperature (20.0 ± 0.5 °C). 57 minutes after conclusion of the first measurement series, a second measurement series was performed for verification purposes.

Table 4.10/1: Measured Values Test Item First Series

Measurement No.	Time (s)	Mass (g)	Surface Tension (mN/m)	Temperature (°C)
1	2.9	0.2246	54.79	19.7
2	5.8	0.2273	55.45
3	8.9	0.2272	55.42
4	11.8	0.2273	55.45
5	14.9	0.2270	55.38
6	17.8	0.2270	55.38
7	20.9	0.2270	55.38
8	23.8	0.2270	55.38
9	26.9	0.2270	55.38
10	29.8	0.2271	55.40
Mean			55.34	-
SD			0.20	-

Table 4.10/2: Measured Values Test Item Second Series

Measurement No.	Time (s)	Mass (g)	Surface Tension (mN/m)	Temperature (°C)
1	3.0	0.2323	56.67	19.9
2	5.9	0.2335	56.96	19.9
3	8.9	0.2331	56.86	19.9
4	11.9	0.2329	56.82	19.9
5	14.9	0.2331	56.86	19.8
6	17.9	0.2330	56.84	19.9
7	20.9	0.2330	56.84	19.9
8	23.9	0.2328	56.79	19.9
9	26.9	0.2328	56.79	19.9
10	29.9	0.2329	56.82	19.9
Mean			56.82	-
SD			0.07	-

 

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 159.61 mg organic carbon/L was obtained, and the concentration of the test item was calculated from the measured DOC and the stated carbon content.

The carbon content in the test item had been determined under non-GLP-conditions in the laboratory Mikroanalytisches Labor Pascher (D-53424 Remagen) with 79.90 % w/w.

The concentration was therefore determined with 199.76 mg test item/L.

Result

During the specified period of time, no relevant changes in the surface tension were detected. Values ranging from 54.79 to 56.96 mN/m were recorded showing no relevant variations. The values of the single determinations showed no significant difference (less than 5 % between mean values of the two measurement series)

Validity

Literature value for the surface tension of H₂O at 18.0 °C: 73.05 mN/m (Vargaftik et al., 1983).

The surface tension of the negative control was determined with 73.03 mN/m at 18.0 °C, therefore showing a difference of 0.03 % from the stated literature value. The difference lies within the accepted range of 1 % deviation from literature value.

The values of the single determinations show no relevant difference (2.67 % between mean values of the two measurement series). All measured values layed clearly below the threshold for surface tension which was stated in the guidelines.

The surface tension of the negative control was determined with a difference of 0.03 % from the stated literature value.

Therefore, the result of the test was considered valid.

Conclusions:

The surface tension of an aqueous solution of the test item (at 90% saturated concentration, measured at 199.76mg/L using a loading rate of 1g/L of test item) was determined as 55.34 ± 0.2 mN/m at 19.7 °C.
According to EU A.5 criteria, as the result is below the threshold value of 60 mN/m, the substance is considered to have surface active potential under the experimental conditions. However, since the structures of the constituents of the substance are not characteristic of true surfactants and that it is not an intended use of the substance (i.e. not a desired property), this conclusion should be taken with caution.

Executive summary:

The surface tension of test item was determined according to EU method A.5 and OECD 115 under GLP using the plate method.

A saturated solution was obtained from an aqueous solution prepared with 1 g/L of test item slow-stirred for 72 h. The concentration of the test item in the 90 % saturated test solution was determined to be 199.76 mg/L (based on analysis of dissolved organic carbon).

The surface tension of the test item in aqueous solution was determined as 55.34 ± 0.2 mN/m at 19.7 °C.

One measurement series was performed for verification (after 57 minutes). No significant changes and thus no significant dependence on time were observed.

Description of key information

Surface tension = 55.34 +/- 0.2mN/m at 19.7°C, at 90% saturation (measured at 199.76 mg/L using a loading rate of 1g/L of test item).

As the result is below the threshold value of 60 mN/m, according to EU.A5 criteria, the substance is considered to have surface-active potential under the experimental conditions. However, since the structures of the constituents of the substance are not characteristic of true surfactant, this conclusion should be taken with caution.

Key value for chemical safety assessment

Surface tension:

55.34

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

199.76

Additional information

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