4'-Butyl-4-ethoxy-2,3-difluoro-1,1'-biphenyl

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 2012-07-13 to 2012-10-08

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:

0.011 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

>= 5.9 - <= 6.1

Preliminary Visual Estimation of the Water Solubility

Different amounts of the test item and water were stirred at room temperature until the mixtures appeared dissolved or the water solubility could be estimated to be below 10 mg/L.

Table 1. Appearance of the test mixtures

Amount of the test item in mg	Total volume in mL	Appearance of mixture
10.4	100	undissolved
12.4	500	undissolved
3.9	500	undissolved

The solubility of the test item in water is below 7.8 mg/L. Therefore, the water solubility had to be determined by the "column elution method".

 

Column elution method

Individual conditions

Column 1:

Rotation period of the fraction accumulator:     90 min per fraction

Average fraction volume:                                            18.3 mL

Flow rate:                                                                          between 11.8 mL/h and 12.9 mL/h

Duration of sampling:                                                   about 47 h (31 fractions)

Column 2:

Rotation period of the fraction accumulator:     45 min per fraction

Average fraction volume:                                            17.3 mL

Flow rate:                                                                          between 22.8 mL/h and 23.2 mL/h

Duration of sampling:                                                   about 47 h (62 fractions)

Column 3 (blank):

Rotation period of the fraction accumulator:     45 min per fraction

Average fraction volume:                                            18.3 mL

Flow rate:                                                                          between 24.3 mL/h and 24.5 mL/h

Duration of sampling:                                                   about 23 h (31 fractions)

Concentration and pH

According to the guideline, the data of the fractions 1 to 5 were not taken into account for the following evaluation. The values for the water solubility were calculated from fractions 22 to 26 for column 1, from the fractions 48 to 52 for column 2 and from the fractions 17 to 21 for column 3. All other fractions were discarded.

Table 2. Column-elution method: Column 1

Fraction No.	V in mL	pH	Water Solubility in µg/L
22	17.8	6.0	10.7
23	17.8	6.1	11.6
24	17.8	6.0	11.3
25	17.8	5.9	11.4
26	17.8	5.9	11.7

Result column 1: Evaluation of the fractions 22 to 26: The water solubility was found to be 0.011 mg/L.

Table 3. Column-elution method: Column 2

Fraction No.	V in mL	pH	Water Solubility in µg/L
48	17.4	5.9	10.3
49	17.4	6.1	10.2
50	17.4	6.0	10.6
51	17.4	5.9	10.5
52	17.4	6.1	10.7

Result column 2: Evaluation of the fractions 48 to 52: The water solubility was found to be 0.010 mg/L.

Table 4. Column-elution method: Column 3 (blank)

Fraction No.	V in mL	pH	Water Solubility in µg/L
17	17.5	5.4	< 4.3*
18	17.0	5.6	< 4.3*
19	17.0	5.8	< 4.3*
20	17.0	5.9	< 4.3*
21	17.0	5.9	< 4.3*

* < indicates below the quantification limit

Result column 3: Evaluation of the fractions 17 to 21: The blank concentration was found to be below the detection limit of 0.004 mg/L.

A recovery of the ‘recheck samples’ was performed and the recovery was found to be between 90.1 % and 96.2 % indicating a sufficient accuracy of the analytical method. The performed coating check was successful.

Conclusions:

The water solubility of the test item at a temperature of 20 °C was determined to be cs = 0.011 mg/L.

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. About 102.5 mg test item were weighed and dissolved in 100 mL acetone. 25 mL of this solution were added to about 3 g sea sand and the mixture was shaken. The solvent was then removed under reduced pressure using a rotary evaporator (50 °C, 10 mbar). The dry residues were placed into the columns of the test apparatus, which were afterwards filled with water (test temperature: 20 °C, water pH at 26.3 °C: 6.0). After a swelling time of 2 h the pump was started to rinse the substance coated sand with distilled water. Two identical columns were prepared - one of them was exposed to a flow rate of about 12.5 mL/h (column 1), the other one to 25.0 mL/h (column 2). Another experiment was performed according to this procedure (flow rate 25.0 mL/h) but without test item ("blank" = column 3). 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 0.011 mg/L at 20 °C (pH = 5.9 – 6.1).

Description of key information

The water solubility of the test item at a temperature of 20 °C was determined to be cs = 0.011 mg/L.

Key value for chemical safety assessment

Water solubility:

0.011 mg/L

at the temperature of:

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). About 102.5 mg test item were weighed and dissolved in 100 mL acetone. 25 mL of this solution were added to about 3 g sea sand and the mixture was shaken. The solvent was then removed under reduced pressure using a rotary evaporator (50 °C, 10 mbar). The dry residues were placed into the columns of the test apparatus, which were afterwards filled with water (test temperature: 20 °C, water pH at 26.3 °C: 6.0). After a swelling time of 2 h the pump was started to rinse the substance coated sand with distilled water. Two identical columns were prepared - one of them was exposed to a flow rate of about 12.5 mL/h (column 1), the other one to 25.0 mL/h (column 2). Another experiment was performed according to this procedure (flow rate 25.0 mL/h) but without test item ("blank" = column 3). 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 0.011 mg/L at 20 °C (pH = 5.9 – 6.1).