Chromium trioxide

Particle size distribution (Granulometry)

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: DIN ISO 4497

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

OECD Guideline 110 (Particle Size Distribution / Fibre Length and Diameter Distributions - Method A: Particle Size Distribution (effective hydrodynamic radius)

Deviations:

not specified

Principles of method if other than guideline:

A dry sieve test according to DIN ISO 4497 will be performed to spearate the biggerparticles (>1 mm) from smaller particles and the particulate matter (<100 µm). The particulate matter will then be tested according to OECD 110 particle size distribution by laser diffraction.

GLP compliance:

yes (incl. QA statement)

Type of method:

sieving

Type of particle tested:

primary particle

Type of distribution:

mass based distribution

No.:

#1

Size:

> 1 mm

Distribution:

99.2 %

No.:

#2

Size:

> 0.1 - < 1 mm

Distribution:

0.8 %

No.:

#3

Size:

< 100 µm

Distribution:

< 0.01 %

The complete sample (657.84 g) was sieved manually using two sieves with a mesh size of 1 mm and 100 µm respectively. The three resulting fractions were quantified gravimetrically. Due to the small amount of particulate matter, no laser diffraction was performed.

Particle fraction	Weight	Amount in %
Share bigger than 1 mm	652.3 g	99.2%
<1 mm but bigger than 100 µm	5.50 g	0.8 g
Particulate matter (<100 µm)	0.06 g	<0.01%
Total	657.87	100%

Conclusions:

The particle size distribution was 99.2% particles bigger than 1 mm, 0.8% of particles <1 mm and >100 µm and <0.01% of particulate matter (<100 µm ).

Executive summary:

A dry sieve test was performed in a GLP-study according DIN ISO 4497 using two sieves with a mesh size of 1 mm and 100 µm respectively. The particle size distribution was 99.2% particles bigger than 1 mm, 0.8% of particles <1 mm and >100µm and <0.01% of particulate matter (<100µm). Due to the fact that no significant amount of particulate matter cound be detected, no laser diffraction was performed.

Reference 2

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: DIN ISO 4497

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

OECD Guideline 110 (Particle Size Distribution / Fibre Length and Diameter Distributions - Method A: Particle Size Distribution (effective hydrodynamic radius)

Deviations:

not specified

Principles of method if other than guideline:

A dry sieve test according to DIN ISO 4497 will be performed to spearate the biggerparticles (>1 mm) from smaller particles and the particulate matter (<100 µm). The particulate matter will then be tested according to OECD 110 particle size distribution by laser diffraction.

GLP compliance:

yes (incl. QA statement)

Type of method:

sieving

Type of particle tested:

primary particle

Type of distribution:

mass based distribution

No.:

#1

Size:

> 1 mm

Distribution:

94.5 %

No.:

#2

Size:

> 0.1 - < 1 mm

Distribution:

5.5 %

No.:

#3

Size:

< 100 µm

Distribution:

< 0.01 %

The complete sample (134.97 g) was sieved manually using two sieves with a mesh size of 1 mm and 100 µm respectively. The three resulting fractions were quantified gravimetrically. Due to the small amount of particulate matter, no laser diffraction was performed.

Particle fraction	Weight	Amount in %
Share bigger than 1 mm	127.56 g	94.5%
<1 mm but bigger than 100 µm	7.46 g	5.5%
Particulate matter (<100 µm)	<0.01 g	<0.01%
Total	135.02 g	100%

Conclusions:

The particle size distribution was 94.5% particles bigger than 1 mm, 5.5% of particles <1 mm and >100 µm and <0.01% of particulate matter (<100 µm).

Executive summary:

A dry sieve test was performed in GLP-study according to DIN ISO 4497 using two sieves with a mesh size of 1 mm and 100 µm respectively. The particle size distribution was 94.5% particles bigger than 1 mm, 5.5 % of particles <1 mm and >100µm and <0.01 % of particulate matter (<100 µm). Due to the fact that no significant amount of particulate matter cound be detected, no laser diffraction was performed.

Reference 3

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: DIN ISO 4497

Deviations:

not specified

Principles of method if other than guideline:

Dry sieve test according to DIN ISO 4497 using a 1 mm and a 100 µm sieve to separate the bigger particles (>1mm) from smaller particles and the particulate matter (<100 µm).

GLP compliance:

yes (incl. QA statement)

Type of method:

sieving

Type of particle tested:

primary particle

Type of distribution:

mass based distribution

Remarks on result:

not determinable because of methodological limitations

The sample consisted of small hard globes which are easily pourable. Shaking these pellets in the original glass bottles does not destroy the globes and no particulate matter is virtually detectable in the original bottle. Sieving these globes immediately leads to destruction of the globes forming a hygroscopic solid but again no dusty matter could be observed. A continuation of the sieving was therefore not possible and the determination was aborted.

Conclusions:

Determination of the particel size was not possible. Sieving these globes immediately leads to destruction of the globes forming a hygroscopic solid but again no dusty matter could be observed. A continuation of the sieving was therefore not possible and the determination was aborted.

Executive summary:

The determination of particle size was performed in a GLP-study using a dry sieve technique according to DIN ISO 4497 and a laser diffraction method (OECD 110).

The sample consisted of small hard globes which are easily pourable. Shaking these pellets in the original glass bottles does not destroy the globes and no particulate matter is virtually detectable in the original bottle. However,

sieving these globes immediately leads to destruction of the globes forming a hygroscopic solid but again no dusty matter could be observed. A continuation of the sieving was therefore not possible and the determination was aborted. The determination of the particle size distribution by laser diffraction was not performed in this study.

Reference 4

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: DIN ISO 4497

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

OECD Guideline 110 (Particle Size Distribution / Fibre Length and Diameter Distributions - Method A: Particle Size Distribution (effective hydrodynamic radius)

Deviations:

not specified

Principles of method if other than guideline:

A dry sieve test according to DIN ISO 4497 will be performed to spearate the bigger particles (>1 mm) from smaller particles and the particulate matter (<100 µm). The particulate matter will then be tested according to OECD 110 particle size distribution by laser diffraction.

GLP compliance:

yes (incl. QA statement)

No.:

#1

Size:

> 1 mm

Distribution:

98.8 %

No.:

#2

Size:

> 0.1 - < 1 mm

Distribution:

1.1 %

No.:

#3

Size:

< 100 µm

Distribution:

< 0.01 %

The complete sample (993.15 g) was sieved manually using two sieves with a mesh size of 1 mm and 100 µm respectively. The three resulting fractions were quantified gravimetrically. Due to the small amount of particulate matter, no laser diffraction was performed.

Particle fraction	Weight	Amount in %
Share bigger than 1 mm	980.72 g	98.8%
<1 mm but bigger than 100 µm	11.42 g	1.1%
Particulate matter (<100 µm)	<0.01 g	<0.01%
Total	992.14 g	99.9%

Conclusions:

The particle size distribution was 98.8% particles bigger than 1 mm, 1.1% of particles <1 mm and >100 µm and <0.01% of particulate matter (<100 µm).

Executive summary:

A dry sieve test according to DIN ISO 4497 and GLP was performed using two sieves with a mesh size of 1 mm and 100 µm respectively. The particle size distribution was 98.8 % particles bigger than 1 mm, 1.1 % of particles <1 mm and >100 µm and <0.01 % of particulate matter (<100 µm). Due to the fact that no significant amount of particulate matter could be detected, no laser diffraction was performed.

Description of key information

Dry sieve tests were performed in GLP-studies according DIN ISO 4497 using two sieves with a mesh size of 1 mm and 100 µm respectively of samples of different suppliers. The particle size in any case show that most of the particles have sizes bigger than 1 mm (< 90 %). The amount smaller than 100 µm was for each sample very low (> 0.01 %).

In one case the particle size distribution could not be done because sieving these globes immediately leads to destruction of the globes forming a hygroscopic solid but again no dusty matter could be observed.