N-butylphosphorothioic triamide

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 18 June 2015 to 27 July 2015

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

OECD harmonised ring method

Surface tension:

66.4 mN/m

Temp.:

20 °C

Conc.:

1 g/L

Remarks on result:

other: Mean corrected value obtained with 5 measurements

Surface tension:

67 mN/m

Temp.:

20 °C

Conc.:

1 g/L

Remarks on result:

other: This surface tension value has not been corrected by the calibration and Harkins-Jordan factors

Surface tension:

66 mN/m

Temp.:

20 °C

Conc.:

1 g/L

Remarks on result:

other: This surface tension value has not been corrected by the calibration and Harkins-Jordan factors

The surface tension of the test item aqueous solution read on the instrument was 67.0 mN/m at 20 °C using the ring method representing the mean of five separate measurements.

The measured surface tension was multiplied by the calibration factor (obtained by the calibration of the apparatus with iultrapure water) a and corrected with Harkins-Jordan factor resulting in a corrected surface tension of 66.4 mN/m.

As the surface tension value was higher than 60 mN/m,the test item is not classified as surface active.

 

Conclusions:

The surface tension of a test item solution at 1g/L and 20°C is 66,4 mN/m. As this value is higher than 60mN/m, the test item is not considered as surface active.

Executive summary:

The surface tension determination was performed using the OECD harmonized ring method according to recognized guidelines (OECD 115 guideline and EU A.5 method) and under GLP.

No deviations from the guidelines was observed during the study.

The surface tension of a test item solution at 1g/L and 20°C is 66,4 mN/m. As this value is higher than 60mN/m, the test item is not considered as surface active.

Description of key information

For the supporting study, the purity of the NBPT test sample was stated as approximately 91% and it contained tetrahydrofuran (THF; EC Number 203-726-8; CAS Number 109-99-9) as an impurity at up to 2%.  According to the REACH dossier for THF, its surface tension is 26.4mN/m at 25ºC (Kirk-Othmer Encyclopedia of Chemical Technology, Index to Volumes 1 - 26, 5th Edition, March 2007).The presence of this THF impurity in the test sample used to determine the surface tension of NBPT provides a plausible explanation for the difference in test results between this study and the key study, which was conducted using 98% pure NBPT. 

Key value for chemical safety assessment

Surface tension:

67

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

1 000

Additional information

The surface tension of the test item aqueous solution read on the instrument was 67.0 mN/m at 20 °C using the ring method representing the mean of five separate measurements.

The measured surface tension was multiplied by the calibration factor (obtained by the calibration of the apparatus with iultrapure water) a and corrected with Harkins-Jordan factor resulting in a corrected surface tension of 66.4 mN/m.

As the surface tension value was higher than 60 mN/m,the test item is not classified as surface active.