2-isopropyl-9H-thioxanthen-9-one

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

26 June 2017 to 04 August 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

column elution method

Key result

Water solubility:

0.34 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

> 5.87 - < 6.45

Remarks on result:

other: RSD = 0.2 %

Details on results:

PRELIMINARY TEST
- The preliminary test at room temperature showed, that the water solubility of the test material was below 9.54 mg/L. The solubility of the test material in water at room temperature was estimated to be < 9.54 mg/L. Therefore, the column elution method was performed.

MAIN TEST
- The mean value and its standard deviation from five consecutive samples taken from the saturation plateau, each measured twice, were calculated for each run. The mean concentrations calculated on two tests using different flows were compared and the repeatability was calculated, which should be better than 30 %.
- The first column yielded in a mean value of the water solubility of 0.335 mg/L with a RSD of 0.01 % which meets the criterion of < 30 %.
- The second column yielded in a mean value of the water solubility of 0.335 mg/L with a RSD of 0.02 % which meets the criterion of < 30 %.
- The third column (blank) showed no test material in the water or any signals in the HPLC chromatograms.
- The two columns with different flow rates yielded in a mean value of the water solubility of 0.335 mg/L with a RSD of 0.2 % which meets the criterion of < 30 %.
- To verify the accuracy of the analytical method freshly prepared standard solutions (prepared with the test material) were measured in between the samples of the column elution method.. The recovery rates should lie between 90 and 110 %.
- The recovery rate of the measured standard solutions was in the range from 96.6 to 107.4 %, which shows a good accuracy of the analytical method.
- Following the measurements, the amount of the test material in the columns was checked. For this purpose, columns 1 and 2 were each purged with 100 mL acetone. 0.01 mL of the acetone solutions were diluted to 1 mL with the eluent and measured by HPLC.
- These measurements show, that 9.66 mg of the test material could be found in column 1 after the main test, which corresponds to 75.3 % of the starting amount. 9.64 mg of the test material could be found in column 2 after the main test, which corresponds to 75.1 % of the starting amount. In both columns enough test material could be found after the main tests to ensure correct performance of the test.

Table 3:Summarised results of column 1 and 2

Column	Mean concentration (mg/L)	Mean measured concentration (mg/L)	Relative standard deviation (RSD) (%)
1	0.335	0.335	0.2
2	0.335

Conclusions:

Under the conditions of this study the water solubility of the test material was 0.34 mg/L.

Executive summary:

The water solubility of the test material was investigated in accordance with the standardised guidelines OECD 105 and EU Method A.6, under GLP conditions.

A preliminary test was performed to give an estimate of the water solubility in order to decide which method had to be used for the main test. In the preliminary test, the solubility of the test material in water at room temperature was estimated to be < 9.54 mg/L, therefore the column elution method was performed. The water solubility of the test material was tested in two columns, a third column was filled with sand which was not loaded with the test material as blank. The concentrations in the fractions were determined by means of HPLC.

The two columns with different flow rates yielded in a mean value of the water solubility of 0.335 mg/L with a RSD of 0.2 % which meets the criterion of < 30 %. The recovery rate of the measured standard solutions was in the range from 96.6 to 107.4 %, which shows a good accuracy of the analytical method.

Following the measurements, the amount of the test material in the columns was checked. For this purpose, columns 1 and 2 were each purged with 100 mL acetone. 0.01 mL of the acetone solutions were diluted to 1 mL with the eluent and measured by HPLC. In both columns enough test material could be found after the main tests to ensure correct performance of the test.

Under the conditions of this study the water solubility of the test material was 0.34 mg/L at 20 °C.

Description of key information

Under the conditions of this study the water solubility of the test material was 0.34 mg/L.

Key value for chemical safety assessment

Water solubility:

0.34 mg/L

at the temperature of:

20 °C

Additional information

The water solubility of the test material was investigated in accordance with the standardised guidelines OECD 105 and EU Method A.6, under GLP conditions.

A preliminary test was performed to give an estimate of the water solubility in order to decide which method had to be used for the main test. In the preliminary test, the solubility of the test material in water at room temperature was estimated to be < 9.54 mg/L, therefore the column elution method was performed. The water solubility of the test material was tested in two columns, a third column was filled with sand which was not loaded with the test material as blank. The concentrations in the fractions were determined by means of HPLC.

The two columns with different flow rates yielded in a mean value of the water solubility of 0.335 mg/L with a RSD of 0.2 % which meets the criterion of < 30 %. The recovery rate of the measured standard solutions was in the range from 96.6 to 107.4 %, which shows a good accuracy of the analytical method.

Following the measurements, the amount of the test material in the columns was checked. For this purpose, columns 1 and 2 were each purged with 100 mL acetone. 0.01 mL of the acetone solutions were diluted to 1 mL with the eluent and measured by HPLC. In both columns enough test material could be found after the main tests to ensure correct performance of the test.

Under the conditions of this study the water solubility of the test material was 0.34 mg/L at 20 °c.