1-3 dihydroxy-2,4bis-(4-(2-sulfooxyethanesulfonyl)-phenylazo) benzene disodium salt

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

GLP compliance:

yes

Type of method:

flask method

Key result

Water solubility:

>= 4.17 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

250 g/L

Incubation duration:

>= 72 - <= 77 h

Temp.:

20 °C

Remarks on result:

completely miscible

1.1     Measurements during Equilibration

The data which was acquired during equilibration time (flask 1A-C, days 1 – 4) is presented in the following table:

Table6.1–a     Equilibration phase

Time [h] (flask)	Temperature [°C]	pH*	Dilution factor	Peak area [mAU*min]	Measured values [g/L]	QC recovery [%]	Difference to previous sample [%]
24 (1A)	20.3	4.83	4000	0.4822	4.50	4.58	-
				0.4873
48 (1B)	20.2	4.75	4000	0.4683	4.38		-2.8
				0.4719
72 (1C)	20.3	4.73	4000	0.5086	4.71		+7.7
				0.5088

* pH during equilibration phase was tested using pH meter, because the solution was too intense in color

Conclusions:

The blendazol Orange is soluble in water

Executive summary:

The solubility of the test substance Blendazol Orange Blendwell in water was determined by measurement of the test substance concentration in the filtrated test solutions using HPLC.

In the pre-test, the test tube with nominal concentrations of 50 – 10 g/L appeared clear. The solubility was expected to lie above 10 mg/L, therefore the flask method was used according to the guideline.

In the main test, the loading rate 250 g/L of the test substance was chosen. Three flasks 1A – C were used during equilibration. Seven vessels (flasks blank and 1C for the sampling point 72 h and flasks 2 – 6) were set onto the shaking apparatus immediately. After 24 ± 2 h, flask 1B (for the sampling point 48 h) and after 48 ± 2 h, flask 1A (for the sampling point 24 h) were set on the shaker and all flasks were shaken for further 24 ± 2 hours at room temperature (20.0 ± 0.5 °C). Then, flasks 1A – C were taken from the shaker, samples were taken, membrane filtered and analysed. Because of a difference of less than 15 % in the concentrations on days 2 and 3 and no upward tendency, the plateau was considered as reached on day 3. The final measurement was performed as determination from flasks 2 – 6 on day

At the plateau, the concentration of Blendazol Orange Blendwell in water had reached.

 

4.17 ± 0.14 g/L at 20.0 °C

4.17 ± 0.14 kg/m³ at 20.0 °C (SI units)

(mean value ± standard deviation of five individual vessels

Description of key information

The solubility ofBlendazol Orange Blendwellin water was determined from the measured test substance concentrations in the filtrated test solutions.

Equilibration time can be considered as approximately 3 days (77 h), as the measured values after 2 d and 3 d did not give significantly different values and no rising tendency was observed over three days.

All replicates showed good correspondence. Standard deviation of the five flasks which were used for the calculation of water solubility at the plateau was 4.17 g/L, corresponding to a relative standard deviation of 3.4 %.

The pH value was 4.70 – 4.73 in all five flasks, the test temperature was in the acceptable range with 20.0 – 20.3 °C over the test duration (measured in the liquid at sampling time points).

No observations arousing doubts concerning the accuracy of the results and the validity of the study were made.

Key value for chemical safety assessment

Water solubility:

4.17 g/L

at the temperature of:

20 °C