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Physical & Chemical properties

Water solubility

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Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2019-07-15 to 2019-07-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
flask method
Key result
Water solubility:
718.2 mg/L
Conc. based on:
test mat.
Loading of aqueous phase:
50 g/L
Incubation duration:
72 h
Temp.:
20 °C
pH:
>= 3.5 - <= 3.7
Details on results:
According to OECD Test Guideline 105 (1995) and Regulation EC No. 440/2008 Method A.6. the water solubility at 20 °C of the test item was determined to be cS = 718.2 mg/L RSD = 1.9 %.

Preliminary Test

The preliminary test at room temperature showed, that the water solubility of the test item was estimated to be > 0.1 g/L and < 1.0 g/L. The observations of the preliminary test are summarized below:

Preliminary test for the water solubility

Amount of test item [mg]

Added volume of water*[mL]

Stirring time ** [min]

Remark

104.22

0.1

--

not dissolved

0.5

--

not dissolved

1.0

3

not dissolved

2.0

3

not dissolved

10.0

3

not dissolved

86.4

6

not dissolved

* 100 mL in total; ** in ultrasonic bath

 

Amount of test item [mg]

Added volume of water [mL]

Stirring time [min]

Remark

9.97

100

~5,500

dissolved

4.95

250

~5,500

dissolved

4.92

500

~5,500

dissolved

The solubility of the test item in water at room temperature was estimated to be higher than 0.01 g/L. Therefore, the flask method was performed.

 

Main Test (flask method)

For the main test three flasks were prepared with a specific amount of test item and water, and one flask only with water. After stirring and centrifugation the aqueous phases were measured by means of UV/VIS spectroscopy. The solution of each flask has been measured twice. The results of these measurements are shown below. The values represented in the table are rounded values. The calculation was carried out with the original not rounded values.

Results of the flask method

Flask

1a

2a

3a

4a

measured value [mg/L]

70.42 / 70.28

72.94 / 73.04

72.05 / 72.16

0 / 0

aliquot of the flask [mL]

1

1

1

1

total volume after 1stdilution [mL]

10

10

10

10

water solubility [mg/L]

704.2 / 702.8

729.5 / 730.4

720.5 / 721.6

0 / 0

average water solubility [mg/L]

703.5

729.9

721.0

0

mean value of the water solubility [mg/L]

718.2

0

standard deviation [mg/L]

13.5

--

relative standard deviation [%]

1.9

--

To verify the accuracy of the analytical method a fresh prepared standard solution (prepared with the test item) was measured in between the samples of the flask method. The results of these measurements are shown below.

Measurement of a standard solution

Standard solution

(nominal value [mg/L])

Measured value [mg/L]

Repeatability [%]

Ü-1 (67.34)

 

66.79

99.2

66.74

99.1

Ü-2 (80.62)

 

80.77

100.2

81.03

100.5

The recovery rate of the measured standard solutions was in the range from 99.1 % to 100.5 %, which shows a good accuracy of the analytical method.

 

Conclusions:
The water solubility of the test item was determined to be 718.2 mg/L at 20 °C.
Executive summary:

The water solubility was determined according to OECD 105 using the shake flask method with UV/VIS. About 5 g test substance was weighed into 100 mL stoppered Erlenmeyer flasks (nine parallels) according to the estimated solubility based on the Preliminary Test. After the addition of 100 mL ultra-pure water, the flasks were agitated at 30 °C. After addition of 100 mL, respectively, of double distilled water to each flask the flasks were stirred at 30 °C for different periods of time (24, 48 and 72 h). After the stirring times enough precipitate remained in the flasks to ensure the saturation of the solution. After stirring at 30 °C the flasks were cooled down to 20 °C and stirred at 20 °C for another 26 h. After 26 h stirring time the contents of the flasks were centrifuged for 30 min at 20 °C with 15000 rpm. For the analytical measurement by means of UV/VIS spectroscopy the centrifuged clear aqueous phases were diluted from 1 mL to 10 mL with double distilled water.The water solubility at 20 °C of the test itemwasdetermined to be 718.2 mg/L.

Description of key information

The water solubility of the test item was determined to be 718.2 mg/L at 20 °C (reference 4.8 -1).

Key value for chemical safety assessment

Water solubility:
718.2 mg/L
at the temperature of:
20 °C

Additional information

The water solubility was determined according to OECD 105 using the shake flask method with UV/VIS (reference 4.8 -1). About 5 g test substance was weighed into 100 mL stoppered Erlenmeyer flasks (nine parallels) according to the estimated solubility based on the Preliminary Test. After the addition of 100 mL ultra-pure water, the flasks were agitated at 30 °C. After addition of 100 mL, respectively, of double distilled water to each flask the flasks were stirred at 30 °C for different periods of time (24, 48 and 72 h). After the stirring times enough precipitate remained in the flasks to ensure the saturation of the solution. After stirring at 30 °C the flasks were cooled down to 20 °C and stirred at 20 °C for another 26 h. After 26 h stirring time the contents of the flasks were centrifuged for 30 min at 20 °C with 15000 rpm. For the analytical measurement by means of UV/VIS spectroscopy the centrifuged clear aqueous phases were diluted from 1 mL to 10 mL with double distilled water.The water solubility at 20 °C of the test item was determined to be 718.2 mg/L.