Iron hydroxide oxide yellow

Particle size distribution (Granulometry)

Link to relevant study record(s)

Reference

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 110 (Particle Size Distribution / Fibre Length and Diameter Distributions)

Principles of method if other than guideline:

The particle size distribution was determined by Image Analysis in accordance with the Council Regulation (EC JRC73260, nanomaterial). The test method is in all essential part identical with the OECD Guideline, Test no. 110, method B.
The pigment was dispersed in about 10 ml of distilled water by means of ultrasound for 1min with the power of 100W. Thus, agglomerates are destroyed forming single or aggregated particles. The particles are placed on a TEM grid and tested by high resolution scanning transmission electron microscopy (HR STEM Company: FEI, QS- No.: 02464; SOP 00013 Vers.2; Reference Material: UER3 922.00).

GLP compliance:

no

Type of method:

microscopic examination

Type of distribution:

counted distribution

Percentile:

D50

Mean:

82 - < 184 nm

Remarks on result:

other: minimal and maximal median diameters measured with Feret method(migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.)

Percentile:

other: 62%

Mean:

> 1 - < 100 other: nm

St. dev.:

4.4

Remarks on result:

other: The quantity of 62 ± 4.4% of all particles based on minimum external dimensions (Q0 Feret min) are between 1 nm and 100 nm.

Statistical Data  Number of particles  1079      Median Feret min [nm]  82 +/- 49  Median Feret max [nm]  184 +/- 146  Q0 Feret min </= 100 nm [%]  62 +/- 4.4  Q0 Feret max </= 100 nm [%]  20 +/- 2.4      Median aspect ratio  2.1 +/- 1.2

Conclusions:

62 +/- 4.4 % of all particles of the measured test material iron hydroxide oxide yellow based on the external dimensions are between 1 nm and 100 nm. Iron hydroxide oxide yellow is a nanomaterial.

Executive summary:

According to the EU definition iron hydroxide oxide yellow is a nanomaterial. The needles are in one direction (minimum) within the specification for nanomaterials. For sample evaluation the external diameter considering (Feret measurements) is chosen due to the shape of the particles. Iron hydroxide oxide yellow shows a rod shape. Therefore the evaluation considering the equivalent circle diameter is inappropriate.

Definition:

“Nanomaterial means a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1nm – 100nm.”

Description of key information

The test material iron hydroxide oxide yellow is considered as a nanomaterial, as 62 +/- 4.4 % of all particles of the test material based on the external dimensions are between 1 nm and 100 nm.

Additional information

Iron hydroxide oxide yellow grades are nanomaterials, according to the EU recommendation of the definition of a nanomaterial 2011/696/EU, Official Journal of the European Union. The rods are in one direction (minimum) within the specification for nanomaterials. For sample evaluation the external diameter (Ferret measurements) is chosen due to the shape of the particles. Iron hydroxide oxide yellow shows a rod shape. Therefore the evaluation considering the equivalent circle diameter is inappropriate. The particle size distribution was determined by Image Analysis in accordance with the Council Regulation (EC JRC73260, nanomaterial). The test method is in all essential parts identical with the OECD Guideline, Test no. 110, method B.

Definition:

“Nanomaterial means a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1nm – 100nm.”

Iron Oxide containing catalysts are generally formed as shaped solids rather than powders. Granulometry data for catalyst products is therefore considered to be a measure of the propensity of a catalyst to produce fines in the course of transportation, handling and use. Test data for catalysts is based on Particle Size Distribution analysis of fines produced in the ASTM D4058 - 96(2011)e1 Standard Test Method for Attrition and Abrasion of Catalysts and Catalyst Carriers. These fines do not typically fall into the definition of nanomaterials according to Commission recommendation 2011/696/EU.