4-hydroxycoumarin

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experiment start date - 06 November 2020; Experiment end date - 22 January 2021.

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:

yes

Type of method:

flask method

Specific details on test material used for the study:

Identification: 4-Hydroxycoumarin
CAS Number: 1076-38-6
Appearance/Physical State: Beige powder
Batch Number: HCN20002
Purity: > 99%
Expiry Date: 26 September 2022
Storage Conditions: Room temperature, in the dark

Water solubility:

0.223 g/L

Conc. based on:

test mat.

Temp.:

20 °C

Remarks on result:

other: pH not available

Details on results:

Preliminary Test: The preliminary estimate of the water solubility at 20.0 ± 0.5 °C was 6.4 x 10E-2 g/L. The solution had a pH of 3.6.

Definitive Test

The mean peak areas relating to the standard and sample solutions are shown in the following table:

Table 7

Solution	Mean Peak Area
Standard 25.0 mg/L	5.5442 x 10^7
Standard 25.0 mg/L	5.5842 x 10^7
Matrix blank	None detected
Sample B1	2.4890 x 10^7
Sample B2	2.4664 x 10^7
Sample B3	2.4805 x 10^7

The concentration (g/L) of test item in the sample solutions is shown in the following table:

Table 8

 

Sample Number	Time Shaken at 30 ºC (hours)	Concentration (g/L)	Solution pH
B1	72	0.224	3.3
B2	48	0.222	3.3
B3	24	0.223	3.3

Mean concentration: 0.223 g/L at 20.0 ± 0.5ºC

Range: 0.222 to 0.224 g/L.

Standard Deviation: 1.0 x 10 ^-3 g/L

Validation

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 5 to 150 mg/L. The results were satisfactory with a correlation coefficient (r) of 1.000 being obtained.

Discussion

As the water solubility was determined during the preliminary test to be above 10^-2 g/L, the flask shaking test was performed.

On completion of the equilibration period, the samples showed excess test item which had dispersed throughout showing hazy sample solutions, and with excess test item at the bottom of the flasks. The solutions were decanted, avoiding excess test item prior to filtration. After filtration, the filtrates were taken for analysis. The filtrates were visually observed to be clear, colorless solutions free from undissolved test item. The filtrates also showed no Tyndall beam effect.

All individual water solubility results were within ± 15% of the mean, thus satisfying the criteria specified in the guidelines.

Conclusions:

The water solubility of the test item has been determined to be 0.223 g/L of solution at 20.0 ± 0.5 °C.

Executive summary:

The determination of water solubility was carried out by the flask method, using a procedure designed to be compatible with Method A.6 Water Solubility of Commission Regulation (EC) No. 440/2008 of 30 May 2008 and Method 105 of the OECD Guidelines for Testing of Chemicals.

A preliminary test was performed in order to select the appropriate method and to determine the approximate amount of test item to be used in the definitive test. HPLC method was used for analysis. The preliminary test to be above 10E-2 g/L, the flask shaking test was performed.

Based on the findings of the study, the water solubility of the test item has been determined to be 0.223 g/L of solution at 20.0 ± 0.5 °C.

Description of key information

The determination of water solubility was carried out by the flask method, using a procedure designed to be compatible with Method A.6 Water Solubility of Commission Regulation (EC) No. 440/2008 of 30 May 2008 and Method 105 of the OECD Guidelines for Testing of Chemicals.

A preliminary test was performed in order to select the appropriate method and to determine the approximate amount of test item to be used in the definitive test. HPLC method was used for analysis. The preliminary test to be above 10E-2 g/L, the flask shaking test was performed.

Based on the findings of the study, the water solubility of the test item has been determined to be 0.223 g/L of solution at 20.0 ± 0.5 °C.

Key value for chemical safety assessment

Water solubility:

0.223 g/L

at the temperature of:

20 °C