Dilutetium oxide silicate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 March 2017 – 29 August 2017

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 (incl. QA statement)

Type of method:

column elution method

Key result

Water solubility:

0.8 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

Lu

Temp.:

20 °C

pH:

6

Remarks on result:

other: mean at flow rates of 12.5 mL/h and 25 mL/h

Key result

Water solubility:

1.1 mg/L

Conc. based on:

test mat. (dissolved fraction)

Remarks:

result calculated based on dissolved Lu measurements

Temp.:

20 °C

pH:

6

Remarks on result:

other: mean at flow rates of 12.5 mL/h and 25 mL/h

Details on results:

Results were validated by:
- Linearity validation: The analysis showed a good linearity of the method (r > 0.990)
- Accuracy validation: Results in dilution mixture showed a good accuracy which indicates acceptable data (recoveries ranged between 75 and 125%).
- Repeatability validation: The results indicated a good precision of the data.
- Specificity: The intensity (CPS) of blank samples measured was negligible or similar to solvent intensity.
- Limit of quantification: For the method in solution the LOQ was set at 30 ng/mL (0.3 mg/L in sample).
- Limit of detection: The LOD was 5 ng/mL.

Results of the preliminary test with 100 mg test sample in 0.1 to 100 mL of milliQ water at pH 6.5 were as follows:

Amount of test item weighed (g)	0.1	0.1	0.1	0.1	0.1	0.1
Volume of water added (mL)	0.1	0.5	1	2	10	100
Solubility (yes/no)	no	no	no	no	no	no

Results of the preliminary test with 10 mg test sample in 1000 mL of milliQ water at pH 6.5 were as follows:

Amount of test item weighed (g)	0.01
Volume of water added (mL)	1000
Solubility (yes/no)	no (after 96 h of agitation and repetition of the test)

Based on the preliminary test results, the solubility was thus below 0.01 g/L, explaining why the main test was performed with column elution method.

Results of the main test:

	Solubility expressed as lutetium content in water (mg/L)	Solubility of lutetium oxide silicate (mg/L)	Mean pH measured	Temperature (°C)
Test 1 (flow 25 mL/h)	0.851	1.115	5.5	20°C
Test 2 (flow 25 mL/h)	0.724	0.948	5.5	20°C
Test 3 (flow 12.5 mL/h)	0.816	1.069	6	20°C
Mean	0.8	1.1	6	20°C

Conclusions:

The water solubility of lutetium oxide silicate was determined according to the EU A.6 method and OECD test guideline 105 in compliance with GLP using the column elution method. The water solubility (expressed as lutetium oxide silicate concentration) was determined to be 1.1 mg/L at pH 6 and 20°C, and was calculated from the measured lutetium content in water which was 0.8 mg/L.

Description of key information

The water solubility of the test substance was determined according to OECD guideline 105 and the EC A.6 method (column elution method) in a GLP study (Klimisch 1, Jean-Baptiste, 2017a) and was found to be 0.8 mg/L at pH 6 and 20°C, when expressed as lutetium content in water, and 1.1 mg/L, when recalculated to lutetium oxide silicate.

Key value for chemical safety assessment

Water solubility:

1.1 mg/L

at the temperature of:

20 °C