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Particle size distribution (Granulometry)

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Reference
Endpoint:
particle size distribution (granulometry)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Experimental starting date: 05 November 2016 Experimental completion date: 10 July 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
other: European Commission Guidance Document EUR 20268 ‘Determination of Particle Size Distribution, Fibre Length and Diameter Distribution of Chemical Substances’ (2002).
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
cascade impaction
Type of particle tested:
primary particle
Type of distribution:
mass based distribution
Specific details on test material used for the study:
Identification: Dichlorobis(η-cyclopentadienyl)titanium
(CAS# 1271-19-8)
Appearance/physical state: red powder
Batch: 07088501022
Purity: 99.8%
Expiry date: 04 March 2019
Storage conditions: room temperature, in the dark
Remarks on result:
not determinable
Remarks:
Too few particles were of a size less than 10.0 µm to allow accurate assessment of the mass median aerodynamic diameter.
Key result
Percentile:
D75
Mean:
< 100 µm
St. dev.:
0

Sieve Screening Test

The results of the sieving procedure are shown in the following table:

Measurement

Result

Mass of test item transferred to sieve

10.52 g

Mass of test item passed through sieve

7.89 g

Percentage of test item less than 100 µm

75.0 %

Cascade Impactor

The results of the cascade impactor procedure are shown in the following table:

Collection stage

Particle size range collected (µm)

Collected mass (g)

Determination 1

Determination 2

Determination 3

Artificial throat

n/a

0.52

0.43

1.03

Cup 1

>10.0

2.2550

2.6524

2.2866

Cup 2

5.5 to 10.0

0.0154

0.0347

0.0065

Cup 3

2.4 to 5.5

0.0047

0.0085

0.0008

Cup 4

1.61 to 2.4

0.0030

0.0025

0.0013

Cup 5

0.307 to 1.61

0.0028

0.0019

0.0004

Final filter

<0.307

0.0004

0.0000[1]

0.0005

Total mass of collected test item

2.8013

3.1300

3.3261

Mass of test item added

2.8617

3.2088

3.2848


[1] A minor apparent weight loss of approximately 1 mg was noted for the final filter stage, for this determination only. This anomaly was assessed as having no significant impact on the validity or integrity of the evaluation of particle size distribution for the test item given the extremely limited proportion of test item within the valid quantification range of the cascade impactor. A collected weight of 0.0000 g was used for continued calculations of cumulative masses and mass percentages.

The cumulative amounts of test item collected in the three determinations for the individual particle size cut-points are shown in the following table:

Particle size cut point (µm)

Cumulative mass (g)

Cumulative percentage (%)

Det 1

Det 2

Det 3

Det 1

Det 2

Det 3

<10.0

0.0263

0.0476

0.0095

0.94

1.52

0.29

<5.5

0.0109

0.0129

0.0030

0.39

0.41

0.09

<2.4

0.0062

0.0044

0.0022

0.22

0.14

0.07

<1.61

0.0032

0.0019

0.0009

0.11

0.06

0.03

<0.307

0.0004

0.0000

0.0005

0.01

0.00

0.02

Overall cumulative percentage with a particle size less than 10.0 µm: ≤1.52%

Overall cumulative percentage with a particle size less than 5.5 µm : ≤0.41%

 Discussion

Sampling for the cascade impactor determinations was performed by rolling the test item container for approximately 10 minutes then sampling from the top, middle and bottom.

The overall results from the cascade impactor were taken as limit values due to the limited but variable low particle size fractions collected across the multiple sampling positions; this gives a worst case scenario. Too few particles were of a size less than 10.0 µm to allow accurate assessment of the mass median aerodynamic diameter.

The inhalable fraction is defined as the mass fraction of particles which can be inhaled by nose or mouth, the thoracic fraction is defined as the mass fraction of particles that passes the larynx and the respirable fraction is defined as the mass fraction of particles that reaches the alveoli.
Conclusions:
Granulometry data acquired for the test item is:
Percentage of test item with an inhalable particle size <100 µm, 75% (measured via sieve)
Percentage of test item with a thoracic particle size <10.0 µm, ≤1.52% (measured via cascade impactor)
Percentage of test item with a respirable particle size <5.5 µm, ≤0.41% (measured via cascade impactor)
Executive summary:

Particle size data was acquired, using a procedure designed to be compatible with the European Commission Technical Guidance Document EUR 20268 Determination of Particle Size Distribution, Fibre Length and Diameter Distribution of Chemical Substances (2002). The results are as follows:

Measurement

Method

Result

Percentage of test item with an inhalable particle size <100 µm

Sieve

75.0%

Percentage of test item with a thoracic particle size <10.0 µm

Cascade impactor

≤1.52%

Percentage of test item with a respirable particle size <5.5 µm

Cascade impactor

≤0.41%

 

Description of key information

Percentage of test item with an inhalable particle size <100 µm, 75% (measured via sieve)

Percentage of test item with a thoracic particle size <10.0 µm, ≤1.52% (measured via cascade impactor)

Percentage of test item with a respirable particle size <5.5 µm, ≤0.41% (measured via cascade impactor)

Additional information