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Physical & Chemical properties

Particle size distribution (Granulometry)

Administrative data

Endpoint:
particle size distribution (granulometry)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
7 October 2016 - 16 January 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
ISO 13320 (Particle size analysis - Laser diffraction methods)
Version / remarks:
2009
Qualifier:
according to
Guideline:
other: CIPAC MT 187 (Particle size analysis by laser diffraction)
Version / remarks:
Handbook K, 2007
Principles of method if other than guideline:
According to REACH Article 13(3) tests on substances shall be conducted in accordance with the test methods laid down in a Commission Regulation or in accordance with other international test methods recognised by the Commission or the Agency as being appropriate. No particle size distribution test method is laid down in regulation (EC) No 440/2008. OECD 110 TG ‘Particle Size Distribution/FibreLength and Diameter Distributions’ dates from 1981 and describes two methods in detail; both methods have restrictions and are not applicable to the entire size range. ECHA’s Guidance on information requirements and Chemical Safety Assessment-Chapter R.7a stipulates that many methods are available for particle size measurements but none of them is applicable to the entire size range. The guidance mentions Laser scattering/diffraction as a method for particles of all kind and makes reference to ISO 13320:2009.
According to Guidance document EUR 20268 (2002), the laser diffraction technique is applicable to particles of respirable and inhalable size. The MMAD can be calculated.
GLP compliance:
yes (incl. certificate)
Type of method:
Laser scattering/diffraction
Type of particle tested:
primary particle
Type of distribution:
volumetric distribution

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Appearance: White powder
- Storage condition of test material: At room temperature
Specific details on test material used for the study:
Relative density: 1.21

Results and discussion

Mass median aerodynamic diameter:
22.652 µm
Geometric standard deviation:
>= 2.556 - <= 2.568
Remarks on result:
other: MMAD is the mean (n= 5) value. 'St.dev.' in table below is the population standard deviation [µm].
Particle sizeopen allclose all
Key result
Percentile:
D10
Mean:
5.363 µm
St. dev.:
0.017
Key result
Percentile:
D50
Mean:
20.592 µm
St. dev.:
0.076
Key result
Percentile:
D90
Mean:
66.281 µm
St. dev.:
0.822
Particle size distribution at different passages
No.:
#1
Size:
< 10 µm
Distribution:
21.15 other: vol%

Any other information on results incl. tables

Coefficient of variation for D50 is < 3%; D10 and D90 are < 5%. These values are within the acceptable limits mentioned in the ISO 13320 standard.

VISUAL OBSERVATION

The substance was observed to be a medium to fine white powder with lumps and clusters. Using a 3.2 objective lens under a microscope, the particles appeared to be crystalline needles and fibres. Using a 40 objective lens under a microscope, the sample was observed to be made up of single crystalline particles and agglomerated particles.  

Applicant's summary and conclusion

Conclusions:
Particle size distribution of the substance: D10 = 5.363 µm, D50 = 20.592 µm and D90 = 66.281 µm. 21.15% by volume was determined to be smaller than 10 µm. The MMAD was determined to be 22.652 µm.

Executive summary:

The particle size distribution of the substance was determined using laser diffraction analysis (small volume wet module) in a GLP study according to ISO 13320 and CIPAC MT 187. Each result is the average of five runs: D10 = 5.363 µm, D50 = 20.592 µm and D90 = 66.281 µm. 21.15% by volume was determined to be smaller than 10 µm. The MMAD was determined to be 22.652 µm.