Didysprosium trioxide

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 October 2017 - 19 January 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

column elution method

Test material

Test material information

Constituent 1

Reference substance name:

Didysprosium trioxide

EC Number:

215-164-0

EC Name:

Didysprosium trioxide

Cas Number:

1308-87-8

Molecular formula:

Dy2O3

IUPAC Name:

dysprosium(3+); oxygen(2-)

Test material form:

solid: particulate/powder

Details on test material:

Name of the test material (as cited in the report): didysprosium trioxide
Physical state: solid
Appearance: (pale) yellow powder
Further information on test item confidential.

Results and discussion

Water solubility

Water solubility 1

Key result

Water solubility:

1.4 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

Dy

Temp.:

20 °C

pH:

6

Remarks on result:

other: Expressed as dysprosium content in water; mean of flow rates 12.5 mL/h and 25 mL/h.

Water solubility 2

Key result

Water solubility:

1.6 mg/L

Conc. based on:

test mat. (dissolved fraction)

Remarks:

Result calculated based on dissolved Dy measurements.

Temp.:

20 °C

pH:

6

Remarks on result:

other: Mean of flow rates 12.5 mL/h and 25 mL/h.

Details on results:

The mean solubility in water is 1.6 mg didysprosium trioxide/L at pH 6 and 20°C.

Results were validated by:
- Linearity validation: The analysis showed a good linearity of the method (r > 0.99).
- Accuracy validation: Results in dilution mixture showed a good accuracy which indicates acceptable data (recoveries ranged between 70 and 110%).
- Repeatability validation: The results indicated a good precision of the data (RSD < 20%).
- Specificity: The intensity (CPS) of blank samples measured was negligible.
- Limit of quantification: 0.15 mg Dy/L

Any other information on results incl. tables

Results of the preliminary test with milliQ water and at pH 6 were:

Amount of test item weighed (g)	0.1	0.1	0.1	0.1	0.1	0.1	0.01
Volume of water added (mL)	0.1	0.5	1	2	10	100	1000
Solubility (yes/no)	No	No	No	No	No	No	No (after > 96 h of agitation of the test solution)

Results of the main test

	Solubility expressed as Dysprosium content in water (mg/L)	Solubility of Didysprosium trioxide in water (mg/L)	Mean pH measured	Temperature (°C)
Test 1 (flow 25 mL/h)	1.4	1.6	6	20
Test 2 (flow 25 mL/h)	1.3	1.5	6	20
Mean (Test 1 and Test 2)	1.4	1.6	6	20
Test 3 (flow 12.5 mL/h)	1.3	1.5	6	20
Mean (12.5 mL/h and 25 mL/h)	1.4	1.6	6	20

Applicant's summary and conclusion

Conclusions:

The water solubility (expressed ad dysprosium oxide concentration) of the test substance was determined to be 1.6 mg/L at pH 6 and 20°C. This result was calculated from the measured dysprosium content in water which was 1.4 mg/L (column elution method).