Reaction mass of C12-14 tert-alkylamines and dimethyl hydrogen phosphate and methyl dihydrogen phosphate

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 September 2017 to 27 September 2018

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:

yes

Remarks:

Due to difficulty in obtaining a reliable aqueous solubility result, an investigation into the formation of micelles was made as part of the aqueous solubility investigation.

Principles of method if other than guideline:

The critical micelle concentration was determined as described below.
The experimental procedure followed that described in EC Directive 92/69/EEC Method A5 and OECD Guideline 115.

Aliquots of test substance (1.08, 10.15 and 100.18 mg) were weighed into each of three 100 mL glass screw topped bottles and double-distilled water (100 mL) added to each one, the concentrations rounded to 10, 100 and 1000 µg/mL. A stirrer was added and the solutions were stirred at room temperature for 2 days. Periodic turbidity measurements were made during this time, the sample being returned to the bottle.

After two days stirring the surface tension was measured on all three samples and on the following dilutions of the 1000 µg/mL: 100, 200, 300, 400, 500, 600, 700, 800 and 900 µg/mL. The test was performed at 20°C using a torsion balance with a 6.366mm diameter platinum ring. Each test was repeated until five consecutive measurements were made.

The apparatus, a Surface Tension Torsion Balance, employing the ring method was calibrated using distilled water to determine a calibration factor, F, which is derived as follows:

F = (σL / σM)

where:
σL = the value given in the literature for the surface tension of water (72.5 mN/m) at 20°C
σM = the measured value of the surface tension of water (mN/m) at 20°C

GLP compliance:

yes (incl. QA statement)

Type of method:

ring method

Specific details on test material used for the study:

- Purity: >98 % This substance has an Unknown or Variable composition, is a Complex reaction product, or a Biological material (UVCB), therefore purity was taken to be 100 %
- Description: Yellow liquid

Key result

Surface tension:

0 other: Could not be determined

Temp.:

20 °C

Conc.:

513 µg/L

Remarks on result:

other: based on critical micelle concentration

Mean surface tension results were first multiplied by the calibration factor and then the Harkins Jordan correction factor as described under the Surface Tension – Critical Micelle Concentration section above and the final corrected mean surface tension values were then plotted against solution concentration to determine the critical micelle concentration.

Conclusions:

The surface tension at 90% saturated, or at 1g/L, could not be ascertained. The surface tension value is 513 µg/mL, based on critical micelle concentration.

Executive summary:

The surface tension of the test substance was investigated in a study performed to the standardized guideline OED 115 under GLP conditions. Due to difficulty in obtaining a reliable aqueous solubility result, an investigation into the formation of micelles was made as part of the aqueous solubility investigation. The surface tension at 90% saturated, or at 1g/L, could not be ascertained. The surface tension value is 513 µg/mL, based on critical micelle concentration.

Description of key information

The surface tension of the test substance was investigated in a study performed to the standardized guideline OED 115 under GLP conditions. Due to difficulty in obtaining a reliable aqueous solubility result, an investigation into the formation of micelles was made as part of the aqueous solubility investigation. The surface tension at 90% saturated, or at 1g/L, could not be ascertained. The surface tension value is 513 µg/mL, based on critical micelle concentration.