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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:
April 13, 2018 to June 11, 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
Deviations:
no
GLP compliance:
no
Type of method:
flask method
Key result
Water solubility:
> 92.7 g/L
Conc. based on:
test mat.
Loading of aqueous phase:
101 g/L
Incubation duration:
24 h
Temp.:
30 °C
pH:
1.2
Key result
Water solubility:
> 91.8 g/L
Conc. based on:
test mat.
Loading of aqueous phase:
102 g/L
Incubation duration:
48 h
Temp.:
30 °C
pH:
1.2
Key result
Water solubility:
> 92.9 g/L
Conc. based on:
test mat.
Loading of aqueous phase:
101 g/L
Incubation duration:
72 h
Temp.:
30 °C
pH:
1.3

1.1  Results     

1.1.1      Preliminary test

In a stepwise procedure, increasing volumes of demineralized water were added at room temperature to a defined amount of the test item. After each addition of an amount of water the mixture was treated with ultrasound for 10 minutes and visually checked for any undissolved particles.

Table3: Results of the preliminary test

Amount of test item

/ mg

Added volume of demineralized water

/ mL

Total volume of demineralized water

/ mL

Appearance of mixture

98.3

0.1

0.1

Sludge formation

0.4

0.5

Viscous solution with precipitates

0.5

1.0

Viscous solution with precipitates

1.0

2

Viscous solution with precipitates

8.0

10

Solution with precipitates

90

100

Dissolved

The preliminary test showed that the water solubility of the test item is > 10 mg/L (between 1.0 to 9.8 g/L). According to the preliminary test the water solubility was determined by the flask method in the main test.

In a first run an initial weight of about 33 g/L was used. As this study determined a water solubility that was in the same range as the initial weight, this run was evaluated as not valid. Therefore the run was repeated with an initial weight of about 100 g/L.

1.1.2      Flask method

The flask method was performed as described. The data for the evaluation are given in Table4. After the equilibration time precipitate was observed in the flasks of the experiments excluding in the blank experiment.

Sample preparation

After the equilibration time of the flask method aliquots of the mixtures were taken and centrifuged (30 minutes with 15000 rpm at 20 °C). Aliquots of the aqueous phases were sampled and filtered twice over a 0.2 µm HPLC syringe filter. Subsequently the aliquots were diluted from 0.1 ml to 10 mL and again from 0.25 mL to 10 mL with the mobile phase.The concentration of the test item was determined by HPLC.

The water solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in Table4.

Table4: Water solubility experiments of the test item

Experiment

24 h experiment

48 h experiment

72 h experiment

Blank

experiment (72 h)

Amount of test item / g

1.01

1.02

1.01

--

Amount of demineralized water / mL

10

10

10

10

Stirring time at 30 °C / h

24

48

72

72

pH at ambient temperature

1.2

1.2

1.3

6.6

Dilution factor

4000

4000

4000

4000

Measured concentration / mg/L

23.23 / 23.13

22.93 / 22.96

23.23 / 23.20

-- / --

Mean concentration / mg/L

23.18

22.95

23.22

--

Water solubility / g/L

92.7

91.8

92.9

--

The measured water solubility values had a mean value of 92 g/L (± 1 g/L). The initial weight of test item of about 101 g/L is assumed as sufficient as during the sample preparation a significant precipitate was observed in the centrifuge tubes.

Therefore the water solubility of the test item is given as 92 g/L without any correction of the purity.

Executive summary:

Final result

The water solubility cSof the test item Basic Blue 45 at a temperature of 20 °C was determined according to the flask method. It was found to be:

                                                                 cS= 92 g/L

Description of key information

The water solubility cSof the test item Basic Blue 45 at a temperature of 20 °C was determined according to the flask method. It was found to be:

                                                                 cS= 92 g/L

Key value for chemical safety assessment

Water solubility:
92 g/L
at the temperature of:
20 °C

Additional information