Registration Dossier
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EC number: 254-413-8 | CAS number: 39318-18-8
Particle size distribution (Granulometry)
Administrative data
Link to relevant study record(s)
- Endpoint:
- particle size distribution (granulometry)
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- N/A to 2009-05-08
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Remarks:
- Well documented, scientifically sound study that used appropriate measurement instrumentation. Work performed following cGMP guidelines. Report was reviewed by laboratory Quality Assurance Department.
- Reason / purpose for cross-reference:
- reference to same study
- Principles of method if other than guideline:
- The particle size was analysed by the Malvern MasterSizer LASER diffracter. This instrument is an ensemble analyser that calculates a volume distribution from the LASER diffraction pattern of a cloud of particles. This raw scatter data is then processed using a complex algorithm and presented on the basis of an equivalent spherical diameter. This instrumentation is approved by ECHA Guidance, 2008 (Chapter R.7a, pg. 148)
- GLP compliance:
- not specified
- Type of method:
- Laser scattering/diffraction
- Type of distribution:
- volumetric distribution
- Key result
- Percentile:
- D50
- Mean:
- 15.94 µm
- Remarks on result:
- other: Migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.
- Key result
- Percentile:
- D10
- Mean:
- 3.78 µm
- St. dev.:
- 0
- Key result
- Percentile:
- D50
- Mean:
- 15.94 µm
- St. dev.:
- 0
- Key result
- Percentile:
- D90
- Mean:
- 47.66 µm
- St. dev.:
- 0
- Endpoint:
- particle size distribution (granulometry)
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- guideline study with acceptable restrictions
- Remarks:
- Well documented study with particle size and surface area examination conducted with sound scientific methodology. However, purpose of study went beyond examination of physical characteristics and few details were provided regarding these determinations.
- Reason / purpose for cross-reference:
- reference to same study
- Principles of method if other than guideline:
- Particle morphology and size were determined by scanning electron microscopy (SEM). Specific surface are (SSA) was determined by nitrogen gas adsorption.
- GLP compliance:
- not specified
- Type of method:
- microscopic examination
- Type of distribution:
- counted distribution
- Mass median aerodynamic diameter:
- > 3.1 - < 4.9 µm
- Geometric standard deviation:
- > 1.5 - < 1.9
- Key result
- Percentile:
- D50
- Mean:
- > 2.1 - < 3.1 other: um (GM aerodynamic fiber diameter for WO2.81, WO2.66 and WO2.51)
- Remarks on result:
- other: Migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.
- Key result
- Percentile:
- other: GM length for WO2.81
- Mean:
- 4 µm
- St. dev.:
- 1.9
- Key result
- Percentile:
- other: GM length for WO2.66
- Mean:
- 4.9 µm
- St. dev.:
- 1.5
- Key result
- Percentile:
- other: GM length for WO2.51
- Mean:
- 3.1 µm
- St. dev.:
- 1.7
Referenceopen allclose all
No specific standard deviation were identified for the particle distribution data although significant robust data was presented in the laboratory report.
The B.E.T. Surface Area of the test substance sample was determined to be 11.12 m2/g.
In addition to the table above, the following results were obtained:
| Study Material | Aspect Ratio (GSD) um | GM width (GSD) | Specific surface area m2/g |
| WO2.81 | 8.3 (1.8) | 0.5 (1.5) | 2.85 +/- 0.02 |
| WO2.66 | 7.9 (1.7) | 0.6 (1.4) | 1.50 +/- 0.07 |
| WO2.51 | 6.9 (1.8) | 0.5 (1.4) | 2.10 +/- 0.02 |
| WO3 | NA (non-fibrous) | NA (non-fibrous) | 0.75 +/- 0.03 |
| WO2.98 | NA (non-fibrous) | NA (non-fibrous) | 11.10 +/- 0.76 |
Description of key information
One tungsten oxide sample was found to have: D10, D50, and D90 = 3.78, 15.94, and 47.66 µm, respectively. The specific surface area of the test substance sample (as determined by B.E.T.) was found to be 11.12 m2/g. The GM aerodynamic fiber diameter for WO2.81, WO2.66 and WO2.51 were found to be >2.1 and <3.1µm for a different sample of tungsten oxide.
Additional information
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