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Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From February 15, 2002 to February 19, 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

Modified method: "Graduated cylinder method".

Principles of method if other than guideline:

"Graduated cylinder method":
The solubility of the test substance was too high to perform the flask method. Therefore approximately 1.5 to 2.0 g of the test substance were weighed into graduated cylinders (10 mL), and solvents (water; buffer pH 5, pH 7, and pH 9) were added in small portions until full dissolution appeared. After each addition of water, the mixture was shook by overhead-rotation. When the test substance was dissolved, the total volume of the solution was read from the graduation of the cylinder. The assessment is made at a temperature of 20°C.

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Remarks:

modified: graduated cylinder method

Specific details on test material used for the study:

Purity: 98.2%
White, coarse grained substance

Key result

Water solubility:

300 000 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

5

Remarks on result:

other: 1.5 to 2.0 g of test substance

Key result

Water solubility:

346 000 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

7

Remarks on result:

other: 1.5 to 2.0 g of test substance

Key result

Water solubility:

373 000 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

9

Remarks on result:

other: 1.5 to 2.0 g of test substance

Results:

Solvent	Test no.	Amount of test substance (mg)	Volume of saturated solution (ml)	Water solubility (g/L)	Mean water solubility (g/L)
Water	1 2 3	1.9973 1.8563 1.8143	- 5.2 5.1	- 357.0 359.3	358 +/- 2
buffer pH 5	1 2 3	1.6332 1.7140 1.7367	5.6 5.1 5.7	291.6 303.4 304.7	300 +/- 7
buffer pH 7	1 2 3	1.9227 1.8870 1.8949	5.7 5.5 5.3	337.3 343.1 357.5	346 +/- 10
buffer pH 9	1 2 3	2.0551 1.9795 2.0441	5.6 5.2 5.5	367.0 380.7 371.7	373 +/- 7

Conclusions:

Under the study conditions, the water solubility of the test substance was determined to be 300000, 346000; and 373000 mg/L at pH 5, 7, and 9, respectively. However, a more suitable water solubility equivalent value, based on critical micelle concentration (CMC), available for the read across substance, Coco TMAC, has been taken forward for the hazard and exposure assessment.

Executive summary:

A study was conducted to determine the water solubility of the test substance, C12 -14 TMAC, according to OECD Guideline 105. A modified flask method was used (Graduated cylinder method) since the solubility was too high to perform the usual flask method. Therefore, approximately 1.5 to 2.0 g of the test substance were weighed into graduated cylinders (10 mL) and solvents (water; buffer pH 5, pH 7, and pH 9) were added in small portions until full dissolution appeared. After each addition of water/buffer, the mixture was shaken by overhead rotation. When the test substance was dissolved, the total volume of the solution was read from the graduation of the cylinder. The assessment was made at a temperature of 20°C. Under the study conditions, water solubility was determined to be 300000, 346000 and 373000 mg/L at pH 5, 7 and 9, respectively (Schneider, 2002).

However, a more suitable water solubility equivalent value, based on critical micelle concentration (CMC), available for the read across substance, Coco TMAC, has been taken forward for the hazard and exposure assessment.

Description of key information

Water solubility was determined based on the CMC value from the surface tension study with the read across substance, Coco TMAC (Bodsch, 2008) as well as according to OECD Guideline 105 for the test substance (Schneider, 2002).

Key value for chemical safety assessment

Water solubility:

1 000 mg/L

at the temperature of:

20 °C

Additional information

Water solubility according to OECD Guideline 105 was determined to be 346 g/L (pH 7). However, a more suitable water solubility equivalent value, based on CMC of 1000 mg/L, available for the read across substance, Coco TMAC, has been taken forward for the hazard and exposure assessment.