Tetrasodium 4-amino-5-hydroxy-6-[[2-methoxy-5-[[2-(sulphonatooxy)ethyl]sulphonyl]phenyl]azo]-3-[[4-[[2-(sulphonatooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2,7-disulphonate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 20, 2015 - April 24, 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Key result

Water solubility:

392 g/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

>= 4.7 - <= 4.8

Details on results:

The water solubility of the test item at 20 °C was determined to be 392 g/L (± 4 g/L).

Individual results

Preliminary visual estimation of the water solubility

In a stepwise procedure, increasing volumes of distilled water were added at room temperature to a defined amount of the test item; where in each following step, the new amount of water is added to the former mixture summing up to the total volume of 1 mL water added. After each addition of an amount of water, the mixture was visually checked for any undissolved particles.

Table4: Results of the preliminary visual estimation of the water solubility

Amount of test item [mg]		Added volume of dist. water [mL]		Total volume [mL]		Appearance of mixture
48.8		0.1		0.1		deep blue mixture^1)
		0.4		0.5		deep blue mixture^1)
		0.5		1.0		dissolved

¹⁾After the addition of water the mixture was treated with ultrasound for 10 minutes.

After the addition of 1 mL dist. water to 48.8 mg of the test item the test item appeared to be dissolved. According to this preliminary visual estimation the water solubility of the test item was > 48.8 g/L. Therefore the preferred method for the main test was the flask method. However, after the addition of less than 1 mL water a deep blue mixture was observed. Because of the dark appearance of this mixture, it was impossible to assess if there were still solid particles of the test item contained. Therefore, prior to the performance of the main test, an additional stirring test was performed to determine the highest amount of test item that can still be stirred sufficiently in a mixture with water.

Table5: Stirring test

Amount of test item [g]		Added volume of dist. water [mL]		Total volume [mL]		Observation
5.42		2		2		could not be stirred at RT
		1		3		could not be stirred at RT
		1		4		could not be stirred at RT
		1		5		could not be stirred at 20 °C
		0.5		5.5		could be stirred at 20 °C

According to the stirring test, mixtures of approx. 985 g/L test item in dist. water were used in the main test.

Flask method

Because of the high solubility of the test item, a stirring test was performed for the determination of the amount of test item to be used in the main test, instead of using the fivefold amount of the solubility estimated in the preliminary test. The data for the evaluation of the main test (flask method) are given in Table 6. After the equilibration time, precipitate was observed in the flasks of the experiments excluding in the blank experiment. For the description of the sample preparation see "details on method".

Table 6: 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]	9.86	9.87	9.87	--
Amount of distilled water [mL]	10	10	10	10
Stirring time at 30 °C [h]	24	48	72	72
pH at 23 °C	4.8	4.7	4.7	5.4
Aliquot of the flasks [g]	0.062	0.061	0.061	0.050
Aliquot of the flasks [mL]	0.049	0.049	0.049	0.050
Dilution to volume [mL]	50	50	50	50
Dilution factor	1020	1020	1020	1000
Measured concentration [[mg/L]	389.5 / 389.7	382.6 / 383.2	379.2 / 379.9	-- / --
Mean concentration [mg/L]	389.6	382.9	379.6	--
Water solubility [ g/L]	395	394	387	--

The water solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in Table 6.

The water solubility of the test item at 20 °C was determined to be 392 g/L (± 4 g/L).

Conclusions:

The water solubility of the test item Reactive Blue 250 at a temperature of 20 °C was determined to be 392 g/L

Executive summary:

The water solubility c_S of the test item Reactive Blue 250 at a temperature of 20 °C was determined according to the flask method described in the European Commission Regulation (EC) No. 440/2008 and in the OECD 105. It was found to be:

 

                                                                 c_S = 392 g/L (± 4 g/L)

Description of key information

The water solubility of the test item was determined by the flask method according to the European Commission Regulations (EC) No. 440/2008 and No. 260/2014, A.6. Water solubility; flask method and according to the OECD test guideline, OECD 105 Water solubility to be 392 g/L

Key value for chemical safety assessment

Water solubility:

392 g/L

at the temperature of:

20 °C

Additional information

 

The water solubility c_Sof the test item Reactive Blue 250 at a temperature of 20 °C was determined according to the flask method described in the European Commission Regulation (EC) No. 440/2008 and in the OECD 105. It was found to be:

 

                                                                 c_S=392 g/L (± 4 g/L)