Dehydrocholic acid

Surface tension

Administrative data

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to

Guideline:

EU Method A.5 (Surface Tension)

Test guideline 2

Qualifier:

according to

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

GLP compliance:

yes

Type of method:

ring method

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

solid: crystalline

Specific details on test material used for the study:

Batch number: 2016110462

Results and discussion

Surface tension

Surface tension:

56.9 mN/m

Temp.:

20 °C

Conc.:

63 mg/L

Any other information on results incl. tables

Results

 

Data in the tables are rounded values taken from Excel spreadsheets which will be archived together with the raw data. The use of Excel spreadsheets for calculations produces more accurate endpoints. These endpoints may slightly differ from the values derived by replacing the rounded values in the formulae given in the methods section.

 

After zero point adjustment, the distilled water surface tension (sg) was determined to be 68.91; therefore the calibration factor was calculated to beF_b = 1.0558.

 

A saturated aqueous solution was prepared weighing 10.12 g of the test item into a 250 mL conical flask, adding 100 mL of water and stirring the suspension overnight.

To obtain a 90% saturated solution (to be tested according to the method’s indications), 90 mL of the previously prepared suspension, filtered by paper filter at 0.45mm, were mixed with 10 mL of water. This clear solution was placed into a 45 mm diameter clean cylindrical glass vessel and the apparatus adjusted to zero.

 

The solution density has not been measured but, taking into consideration the test item water solubility, the distilled water density value has been used.

 

Six measurements were performed at 20 ± 0.5°C maintained through a thermostatic liquid bath with external circulation.

Table2 Surface tension at 20°C

 

Measurements	Test item 90% saturation (mN/m)
1^st	53.9
2^nd	53.9
3^rd	53.9
4^th	53.9
5^th	53.7
6^th	53.9
Average value	53.9
S.D.	0.09
RSD%	0.16%
Fb	1.0558
Corrected value	56.9

Applicant's summary and conclusion

Conclusions:

Surface tension of the substance is 56.9 mN/m (surface-active material).