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Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019-11-11 to 2020-03-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Type of method:

column elution method

Specific details on test material used for the study:

- Batch No.: 2019002
- Purity: 98.39 %
- Physical state: white solid
- Storage conditions: Ambient temperature (10–30 °C)
- Expiry date: 2020-10-21

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
The sample was tested as received. No further preliminary treatment such as drying or milling was performed.

Key result

Water solubility:

0.018 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

>= 5.5 - <= 6.1

Details on results:

Preliminary test:
Three preliminary tests were carried out with specified amounts of the test item (see table below) and demineralized water. After each addition of water, the mixture was stirred for at least 24 hours, and visually checked for any undissolved particles. The preliminary test showed that the water solubility of the test item was < 10 mg/L. According to the preliminary test the water solubility was determined by the column elution method in the main test.
Main test:
Column elution
102.9 mg of the test item were dissolved in 100 mL acetone using the ultrasonic bath for 3 minutes. For charging the columns in each case 25 mL of the test item solution was added to about 3 g of sea sand and the mixtures were shaken. The solvent was then removed under reduced pressure using a rotary evaporator (40 °C, approx. 30 mbar). The dry residues were placed into the columns of the test apparatus, which have afterwards been filled with water (test temperature: 20 °C; water pH at 23 °C: 5.3).
After a swelling time of 2 h pumps were started to rinse the test item coated sand with demineralized water. At the end of the study it was confirmed that residual test item remained on the columns. The residual test item was eluted with 50 mL acetone.
As blank value demineralized water was tested. No signal was detected in the range of the retention time of the test item. The concentration of the test item was quantified by HPLC.
The water solubility of the test item was below the quantification limit of 43 µg/L by applying analytical method 1. Applying analytical method 2, the water solubility values given in Table 2 and 3 (see box "Any other information on results inlc. tables") resulted for the test item. According to OECD TG 105 the value of two columns with different flows should not differ by more than 30%. Since this criterion has been met in this study, with a relative standard deviation of 13% of both columns, the mean value of the columns of 18 µ/L resulted for the water solubility of the test item.

Table 1: Results preliminary test

Amount of test item / mg	Total volume of demineralized water/mL	Appearance of mixture
16.10	100.00	not dissolved
11.10	500.00	not dissolved
4.70	500.00	not dissolved

Table 2: Column elution method (column 1, approx. 12.5 mL/h)

Fraction no.	V/mL	pH	Resulting water solubility µg/L
22.00	19.00	6.00	20.54
23.00	19.00	5.90	19.90
24.00	19.00	6.10	20.71
25.00	19.00	5.90	20.01
26.00	19.00	5.90	19.43

ln column 1 the mean water solubility applying analytical method 2 was found to be 20.1 µg/L.

Table 3: Column eltution method (column 2, approx. 25.0 mL/h)

Fraction no.	V/mL	pH	Resulting water solubility µg/L
48.00	17.50	5.80	17.32
49.00	17.50	6.00	16.51
50.00	17.50	6.00	16.18
51.00	17.50	6.00	17.19
52.00	17.50	6.10	16.81

ln column 2 the mean water solubilíty applying analytical method 2 was found to be 16.8 µg/L.

Table 4: Coating check

	Amount of testitem used for coating [mg]	Measured concentration of test item in eluate [mg/L]	Amount of test item eluted [mg]	Analytical method
Column 1 (12.5 mL/h)	25.7	0.327 / 0.329	16.4	1
		0.327 / 0.328	16.4	2
Column 2 (25.0 mL/h)		0.301 / 0.3001	15	1
		0.300 / 0.300	15	2

The coating check was successful. Enough test item remained on the columns.

Conclusions:

The water solubility of the test item, using the column elution method, is 0.018 mg/L at 20 °C.

Executive summary:

The water solubility of the test item was determined according to the "column elution method" as described in EU method A.6 and OECD TG 105. The water solubility was found to be 0.018 mg/L at a temperature of 20 °C.

Description of key information

The water solubility of the registered substance was found to be 0.018 mg/L at a temperature of 20 °C.

 

 

Key value for chemical safety assessment

Water solubility:

0.018 mg/L

at the temperature of:

20 °C