1-amino-4-hydroxy-2-[(6-hydroxyhexyl)oxy]anthraquinone

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

April 27, 2018 - May 04, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

no

Type of method:

column elution method

Key result

Water solubility:

< 0.21 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

989 mg/L

Temp.:

20 °C

pH:

> 6.4 - < 7.2

Preliminary  test

Three preliminary tests were carried out with specified amounts of the test item and 100 mL, 500 mL and 1000 mL demineralized water, respectively. After each addition of an amount of water, the mixture was stirred for at least 24 hours, and visually checked for any undissolved particles.

Table4: Results of the preliminary test

Amount of test item / mg	Total volume of demineralized water / mL	Appearance of mixture
12.4	100	not dissolved
14.6	500	not dissolved
8.9	1000	not dissolved

The preliminary test showed that the water solubility of the test item is < 10 mg/L. According to the preliminary test the water solubility was determined by the column elution method in the main test.

Column elution  method

98.9 mg of the test item were dissolved in 100 mL tetrahydrofuran. 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. 20 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 24 °C: 7.0). 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 THF. As blank value the used 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. Refer to Table 5 to Table 7 for results.

Column 1:

Rotation period of the fraction collector:                 90 min per fraction

Duration of sampling:                                             about 50 h (33 fractions)

Table5: Column elution method, column 1 (approximately 12.5 mL/h)

Fraction no.	V / mL	pH	water solubility /µg/L
20	16.0	6.4	<208
21	15.5	7.0	<208
22	15.5	7.1	<208
23	15.5	7.2	<208
24	15.0	7.0	<208

The water solubility was found to be below the quantification limit of 208 µg/L.

 

 

 

Column 2:

Rotation period of the fraction collector:       45 min per fraction

Duration of sampling:                                    about 46 h (61 fractions)

Table6: Column elution method, column 2 (approximately 25.0 mL/h)

Fraction no.	V / mL	pH	water solubility /µg/L
40	12.5	6.8	<208
41	12.5	6.9	<208
42	13.0	7.0	<208
43	13.0	7.0	<208
44	13.5	7.0	<208

The water solubility was found to be below the quantification limit of 208 µg/L.

In both columns the concentration of five consecutive fractions was constant within ± 30 %. No increasing or decreasing tendency was observed.

Coating check:

Table7: Coating check

	Amount of test item used for coating / mg	Measured concentration of test item in eluate / mg/L	Amount of test item eluted / mg
Column 12.5 mL/h	24.7	3.588 / 3.621	18.02
Column 25.0 mL/h		3.977 / 4.018	19.99

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

The water solubility c_S of the test item Disperse Red 91 was below the quantification limit of 208 µg/L (mean value of the columns).

Executive summary:

The water solubility c_S of the test item Disperse Red 91 at a temperature of 20 °C was determined according to the column elution method. It was found to be below the quantification limit:

c_S < 0.21 mg/L

Description of key information

The water solubility c_S of the test item Disperse Red 91 at a temperature of 20 °C was determined according to the column elution method. It was found to be below the quantification limit:

c_S < 0.21 mg/L