3-Butoxy-7-ethoxy-4,6-difluoro-dibenzothiophene

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016-12-22 to 2017-01-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

no

Type of method:

column elution method

Key result

Water solubility:

< 0.003 mg/L

Conc. based on:

test mat.

Incubation duration:

68 h

Temp.:

20 °C

pH:

6.1

Preliminary visual estimation of the water solubility

Three preliminary tests were carried out with specified amounts of the test item and 100 mL and 500 mL demineralized water, respectively. After each addition of an amount of water, the mixture was stirred for at least 24 hours, and visually checked for any undissolved particles. The preliminary visual experiments showed that the water solubility of the test item is < 10 mg/L. According to the preliminary visual estimation in the main test the water solubility was determined by the flask method.

 

Column elution method

 

105.0 mg of the test item were dissolved in 100 mL acetone. For charging the columns in each case 25 mL of the test item solution was added to about 3 g of sea sand and the mixtures were shaken. The solvent was then removed under reduced pressure using a rotary evaporator (40 °C, approx. 20 mbar). The dry residues were placed into the columns of the test apparatus, which have afterwards been filled with water (test temperature: 20 °C; water pH at 23 °C: 5.5). After a swelling time of 2 h pumps were started to rinse the test item coated sand with demineralized water. At the end of the study it was confirmed that residual test item remained on the columns. The residual test item was eluted with 50 mL acetone. As blank value the used demineralized water was tested. No signal was detected in the range of the retention time of the test item. The concentration of the test item was quantified by HPLC.

 

 

Column 12.5 mL/h:

Rotation period of the fraction collector: 90 min per fraction

Duration of sampling: about 68 h (45 fractions)

 

Column elution method, column 12.5 mL/h

Fraction no.	V /mL	pH	water solubility µg/L
36	18.0	6.1	<24.8
37	18.0	6.2	<24.8
38	18.0	6.1	<24.8
39	18.0	6.1	<24.8
40	18.0	6.2	<24.8

The water solubility was found to be below the quantification limit of 24.8 µg/L.

 

Column 25.0 mL/h:

Rotation period of the fraction collector: 45 min per fraction Duration of sampling: about 68 h (90 fractions)

 

Table 6: Column elution method, column 25.0 mL/h

Fraction no.	V /mL	pH	water solubility µg/L
76	15.5	6.1	<24.8
77	15.5	6.2	<24.8
78	15.5	6.2	<24.8
79	15.5	6.1	<24.8
80	15.5	6.1	<24.8

The water solubility was found to be below the quantification limit of 24.8 µg/L. In both columns the concentration of five consecutive fractions was constant within ±30%. No
increasing or decreasing tendency was observed.

 

The water solubility of the test item at a temperature of 20 °C was determined according to the column elution method. It was found to be below the quantification limit of 0.025 mg/L.

Conclusions:

The water solubility of the test item was determined to be below 0.0025 mg/L (LOQ) at 20 °C.

Executive summary:

The water solubility of the test item was determined according to OECD 105 and Regulation (EC) No. 440/2008 method A.6 using the column elution method with HPLC analysis (reference 4.8-1). 105.0 mg of the test item were dissolved in 100 mL acetone. For charging the columns in each case 25 mL of the test item solution was added to about 3 g of sea sand and the mixtures were shaken. The solvent was then removed under reduced pressure using a rotary evaporator (40 °C, approx. 20 mbar). The dry residues were placed into the columns of the test apparatus, which have afterwards been filled with water (test temperature: 20 °C; water pH at 23 °C: 6.1). After a swelling time of 2 h, pumps were started to rinse the test item coated sand with demineralized water. At the end of the study it was confirmed that residual test item remained on the columns. The concentration of test item was determined by means of HPLC. The pH of each sample was recorded. The water solubility of the test item was determined to be below the quantification limit of the analytical method 0.025 mg/L at 20 °C (pH = 6.1).

Description of key information

The water solubility of the test item was determined to be below 0.0025 mg/L (LOQ) at 20 °C.

Additional information

The water solubility of the test item was determined according to OECD 105 and Regulation (EC) No. 440/2008 method A.6 using the column elution method with HPLC analysis (reference 4.8-1). 105.0 mg of the test item were dissolved in 100 mL acetone. For charging the columns in each case 25 mL of the test item solution was added to about 3 g of sea sand and the mixtures were shaken. The solvent was then removed under reduced pressure using a rotary evaporator (40 °C, approx. 20 mbar). The dry residues were placed into the columns of the test apparatus, which have afterwards been filled with water (test temperature: 20 °C; water pH at 23 °C: 6.1). After a swelling time of 2 h, pumps were started to rinse the test item coated sand with demineralized water. At the end of the study it was confirmed that residual test item remained on the columns. The concentration of test item was determined by means of HPLC. The pH of each sample was recorded. The water solubility of the test item was determined to be below the quantification limit of the analytical method 0.025 mg/L at 20 °C (pH = 6.1).