Zirconium diboride

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 July 2016 - 03 November 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2017

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:

Zirconium diboride

EC Number:

234-963-5

EC Name:

Zirconium diboride

Cas Number:

12045-64-6

Molecular formula:

ZrB2

IUPAC Name:

zirconium diboride

Test material form:

solid: particulate/powder

Details on test material:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: ZrB2-3.2/14
- Expiration date of the lot/batch: 04 March 2017
- Purity: 99%
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Controlled room temperature (15-25 ºC, below 70% relative humidity), protected from light and humidity
OTHER SPECIFICS:
Description: Grey powder (the colour was determined by visual inspection upon arrival at test facility)
Safety precautions: Routine safety precautions (lab coat, gloves, safety glasses, face mask) for unknown materials were applied to assure personal health and safety.

Results and discussion

Water solubility

Water solubility 1

Key result

Water solubility:

< 0.003 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

zirconium

Temp.:

20 °C

pH:

6.4

Remarks on result:

other: LOQ = 0.003 mg Zr/L

Water solubility 2

Key result

Water solubility:

0.27 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

boron

Temp.:

20 °C

pH:

6.4

Details on results:

Results were validated by:
- Linearity validation: The analysis showed a good linearity of the method (r > 0.99)
- Accuracy validation: Results of accuracy 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: The LOQ was set at 10 ng/mL for B (0.1 mg/L in the sample) and 0.3 ng/mL for Zr (0.003 mg/L in the sample).
- Limit of detection: The LOD was found to be 2.5 ng/mL for B and 0.075 ng/mL for Zr.

Any other information on results incl. tables

Results of the preliminary test with milliQ water as the solvent at pH 6.4 are 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)

Since the solubility was < 0.01 g/L, the main test was performed according to the column elution method.

Results of the main test, expressed as boron:

	Solubility expressed as boron content in water (mg/L)	Mean pH measured	Temperature (°C)
Test 1 (flow 25mL/hour)	0.26	6.4	20°C
Test 2 (flow 25 mL/hour)	0.27	6.4	20°C
Test 3 (flow 12.5 mL/hour)	0.27	6.4	20°C
Mean	0.27	6.4	20°C

The mean solubility in water was 0.27 mg B/L at pH 6.4 and at 20°C.

Results of the main test expressed as zirconium:

	Solubility expressed as zirconium content in water (mg/L)	Mean pH measured	Temperature (°C)
Test 1 (flow 25mL/hour)	<LOQ	6.4	20°C
Test 2 (flow 25mL/hour)	<LOQ	6.4	20°C
Test 3 (flow 12.5mL/hour)	<LOQ	6.4	20°C
Mean	<LOQ (0.003 mg/L)	6.4	20°C

The mean solubility in water was below the LOQ at pH 6.4 and at 20°C (expressed as zirconium content in water).

Applicant's summary and conclusion

Conclusions:

The water solubility (expressed as boron and zirconium content in water) of the test substance was determined to be 0.27 mg/L (for boron) and < LOQ (0.003 mg/L) (for zirconium) at pH 6.4 and 20°C.