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Particle size distribution (Granulometry)

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Endpoint:
particle size distribution (granulometry)
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
March 2015
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study is well described. However, overestimation of Z-average is possible with this technique. There is a large variation in scattering power and larger particles may mask the presence of smaller particles. In the present study the data quality was too poor and the sample was too polydisperse for distribution analysis. Larger particles (oversizers) were present which hindered the analysis. Furthermore sample fluorescence and sample absorbance (coloured samples) is reported. Therefore the study is considered reliable with restrictions. It can only be used as supporting study.
Qualifier:
no guideline followed
Principles of method if other than guideline:
The particle size distribution was determined by a Dynamic Light Scattering (DLS) method.
GLP compliance:
no
Type of distribution:
other: intensity
Percentile:
D50
Remarks on result:
other: Migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.

Particle size distribution based on mean intensity of 278PE:130904 (PA062362-002) treated with the dispersant Novachem 2 % : See attached graph.

The size quality report gave the following remark :

RESULT DOES NOT MEET QUALITY CRITERIA

Multimodal fit error high

* Data quality too poor for distribution analysis

* Sample too polydisperse for distribution analysis

In range figure is low (74%)

* Presence of large or sedimenting particles

* Sample fluorescence

* Sample absorbance (coloured samples)

This means that there are oversizers present, which can be seen in the raw correlation data graph which is given in the attached report.

All the particle size distribution graphs and raw correlation data graphs of all the other samples – whether treated with Novachem 2 % or with MQ water – look the same.

To verify the homogenity of the pigments, the sample preparation is repeated (starting from the weighing) for each pigment.

The average particle size (z-average) was > 100 nm for all samples and all treatments (see Table below).

Every pigment contains oversizers : see raw correlation data graphs in the attached report, very high PdI and PdI width values.

Treatment with Novachem 2 % : ultra sound high energy treatment resulted in smaller Z-average values than only vortex treatment.

Treatment with MQ water : only vortex treatment gave no signal at all (only tested for batch130903).

After ultra sound high energy treatment, Novachem 2 % as dispersant resulted in smaller Z-average values than MQ water as dispersant.

The Z-average values for 1 sample were not reproducible (except for batch130903), this is due to the presence of oversizers, or to inhomogenities in the pigment, or a combination of both.

 

Conclusions:
The particle size distribution was determined by a Dynamic Light Scattering (DLS) method. All measured particles that were larger than 100 nm. However, the data quality was poor and the sample was too polydisperse for distribution analysis. Larger particles (oversizers) were present which hindered the analysis. Furthermore sample fluorescence and sample absorbance (coloured samples) is reported. Therefore the study is considered reliable with restrictions. It can only be used as supporting study.
Endpoint:
particle size distribution (granulometry)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
March 2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
no guideline followed
Version / remarks:
See remarks under "Principles of method other than guideline"
Principles of method if other than guideline:
To determine if Bismuth oxy-iodide/bromide falls under the definition of a nanomaterial as defined in EU recommendation 2011/696/EU, the following investigations were performed:
o Specific surface area analysis by BET (physical adsorption of a gas on the surface of the solid as developed by Brunauer, Emmett and Teller) combined with powder density analysis by use of pycnometer
o Scanning Electron Microscope (SEM)
GLP compliance:
no
Type of method:
microscopic examination
Type of distribution:
counted distribution
Percentile:
D50
Remarks on result:
other: Migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.
No.:
#1
Size:
< 100 other: nm
Distribution:
43.75 %
Remarks on result:
other: Batch 130903 (BiOI0.4Br0.6), n= 48
No.:
#2
Size:
< 100 other: nm
Distribution:
34.09 %
Remarks on result:
other: Batch 130904 (BiOI0.6Br0.4), n= 44
No.:
#3
Size:
< 100 other: nm
Distribution:
15 %
Remarks on result:
other: Batch 130905 (BiOI0.8Br0.2), n= 40

SEM Results

See above

BET & powder density results

 

Product

Batch

Specific surface area (m2/g)

Powder Density

(g/cm3)

specific surface area by volume1

(m2/cm3)

Nanomaterial as defined by point 5 of 2011/696/EU

278PE

130903

5.51

8.00

44.08

No (<60 m2/cm3)

278PE

130904

3.59

8.02

28.79

278PE

130905

2.51

8.01

20.11

 

BET & powder density reports are available in the attachments.

 

1: Specific surface area by volume is obtained by multiplication of powder density and specific surface are

Conclusions:
The specific surface area of the measured samples as determined from BET and powder density results is < 60 m2/cm3.
SEM analysis revealed that <50% of the particles had a diameter of <100 nm. Therefore, it is concluded that the substanceshould not be regarded as a nanomaterial under the definition of EU recommendation 2011/696/EU.

Description of key information

 The specific surface area of the measured samples as determined from BET and powder density results is < 60 m2/cm3. SEM analysis revealed that <50% of the particles had a diameter of <100 nm. Therefore, it is concluded that the substance should not be regarded as a nanomaterial under the definition of EU recommendation 2011/696/EU. This issupported by the particle size distribution as determined by a Dynamic Light Scattering (DLS) method. All measured particles were found to be larger than 100 nm.

Additional information

SEM analysis, BET and powder density determinations are available in a report by Cappelle Pigments (2015). The three studies that are part of this report are regarded as key studies. The test results indicate that the majority of the particles have a diameter > 100 nm.

Attempts were also made to determine the particle size distribution with DLS. All measured particles were larger than 100 nm. However, the data quality was poor and the sample was too polydisperse for distribution analysis. Larger particles (oversizers) were present which hindered the analysis. On the other hand, sample fluorescence and sample absorbance (coloured samples) is reported. Therefore the study is considered reliable with restrictions and it is used as supporting study.