Tris[oxalato(2-)]digadolinium

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 June 2016 - 26 January 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

Water solubility:

2.8 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

Gd

Temp.:

20 °C

pH:

4

Remarks on result:

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

Water solubility:

5.1 mg/L

Conc. based on:

test mat. (dissolved fraction)

Remarks:

Result calculated based on dissolved Gd measurements

Temp.:

20 °C

pH:

4

Remarks on result:

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

Water solubility:

0.6 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

Gd

Temp.:

20 °C

pH:

6.4

Remarks on result:

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

Water solubility:

1 mg/L

Conc. based on:

test mat. (dissolved fraction)

Remarks:

Result calculated based on dissolved Gd measurements

Temp.:

20 °C

pH:

6.4

Remarks on result:

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

Key result

Water solubility:

0.7 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

Gd

Temp.:

20 °C

pH:

7

Remarks on result:

other: Mean at flow rates 12.5 mL/h and 25 mL/h

Key result

Water solubility:

1.3 mg/L

Conc. based on:

test mat. (dissolved fraction)

Remarks:

Result calculated based on dissolved Gd measurements

Temp.:

20 °C

pH:

7

Remarks on result:

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

Water solubility:

0.7 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

Gd

Temp.:

20 °C

pH:

9

Remarks on result:

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

Water solubility:

1.3 mg/L

Conc. based on:

test mat. (dissolved fraction)

Remarks:

Result calculated based on dissolved Gd measurements

Temp.:

20 °C

pH:

9

Remarks on result:

other: Mean at flow rates 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 > 0.99)
- 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 1 ng/mL.
- Limit of detection: The LOD was found to be 0.1 ng/mL.

Conclusions:

The water solubility (expressed as gadolinium oxalate concentration) of the test substance was determined to be 5.1 mg/L, 1.0 mg/L, 1.3 mg/L and 1.3 mg/L at pH 4, 6.4, 7 and 9, respectively, and was calculated from the measured gadolinium content in water which was 2.8 mg/L at pH 4, 0.6 mg/L at pH 6.4, and 0.7 mg/L at pH 7 and 9. Results of this study can be considered reliable without restriction.

Description of key information

In a GLP study (Klimisch 1, Jean-Baptiste, 2017) based on the OECD 105 and EC A.6 test guidelines, the water solubility of gadolinium oxalate was determined to be 5.1 mg/L at pH 4, 1.0 mg/L at pH 6.4, and 1.3 mg/L at pH 7 and pH 9, expressed as gadolinium oxalate content in water at 20°C and extrapolated from the measured values of dissolved gadolinium which were 2.8 mg/L at pH 4, 0.6 mg/L at pH 6.4, and 0.7 mg/L at pH 7 and pH 9.

This study was assigned as key study.

Key value for chemical safety assessment

Water solubility:

1.3 mg/L

at the temperature of:

20 °C