Tall oil, sodium salt

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-10-01 to 2010-11-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

Version / remarks:

12 May 1981

Deviations:

yes

Remarks:

The surface tension result was not corrected using the Harkins-Jordan correction table as the correction is not applicable to the apparatus used. Once calibrated, direct reading for surface tension obtained was within required accuracy of ± 0.5 mN/m.

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Deviations:

yes

Remarks:

The surface tension result was not corrected using the Harkins-Jordan correction table as the correction is not applicable to the apparatus used. Once calibrated, direct reading for surface tension obtained was within required accuracy of ± 0.5 mN/m.

GLP compliance:

yes (incl. QA statement)

Type of method:

ring method

Key result

Surface tension:

55.5 mN/m

Temp.:

21.5 °C

Conc.:

0.057 g/L

Sample Solution Concentration:

Concentrations obtained from the calibration curve and corrected for dilution factor (5) are shown in table 1:

Table 1: Sample Solution Concentration

Solution	TOC Concentration (mg/l)
Matrix blank	<LOQ*
Sample A	57.2
Sample B	57.5
Sample solution concentration = 5.74 X 10^-2g/l (TOC)

*1.00 mg/l is the LOQ of the instrument

Calibration Factor (f)

The readings, temperatures and the corresponding calibration factors for reverse osmosis water are shown in table 2:

Table 2: Reverse Osmosis calibration factor

Reading (mN/m)	Temperature (°C)	Literature value (mN/m)	Calibration factor
73.5	21.6	72.47	0.986
73.0	21.6	72.47	0.993
72.5	21.6	72.47	1.000
73.0	21.6	72.47	0.993
73.0	21.6	72.47	0.993
73.0 72.5 73.0	21.6 21.6 21.6	72.47 72.47 72.47	0.993 1.000 0.993
Mean calibration factor of the last 6 readings = 0.995

Sample Solution readings:

The readings, times and temperatures for the sample solution are shown in table 3:

Table 3: Sample solution readings

Time (Mins)	Reading (mN/m)	Temperature (°C)
95	54.5	21.6
108	55.0	21.6
115	55.5	21.6
125	56.0	21.6
133	56.0	21.6
145	56.0	21.6
154	55.5	21.6

 

Mean Reading                  55.8 mN/m

Surface Tension                reading X calibration factor

                                         55.8 X 0.995

                                         55.5 mN/m

Temperature                     21.5 ± 0.5 °C

pH of sample solution    8.67

Conclusions:

A surface tension of 55.5 mN/m at 21.5 ± 0.5°C for a 0.0574 g/L solution was determined for the substance. The result was obtained in a reliable study conducted according to OECD 115, and in compliance with GLP.

Description of key information

Surface Tension: 55.5 mN/m at 21.5 ± 0.5°C (OECD 115)

Key value for chemical safety assessment

Surface tension:

55.5

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

0.057

Additional information

A surface tension value of 55.5 mN/m at 21.5 ± 0.5°C and concentration of 0.0574 g/L was determined for the registered substance in accordance to an appropriate test guideline. The substance is found to be slightly surface active.

 

In other supporting studies from the public domain, a surface tension value which ranges from 32.2 - 32.7 dynes/cm (32.2 - 32.7 mN/m) at 30°C was reported for the registered substance. The presence of unsaponifiable matter in the samples tested could result in the lower surface tension value.

 

The surface tension of some samples could not be determined due to the formation of micro-emulsions during the water solubility determination. The registered substance is a UVCB substance, variations in the results could be as a result of the nature and composition of the samples tested.