Methyl 2,4-dihydroxy-3,6-dimethylbenzoate

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

Study period:

16 August 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

according to guideline

Guideline:

ISO 13320 (Particle size analysis - Laser diffraction methods)

Version / remarks:

2009

Qualifier:

according to guideline

Guideline:

other: CIPAC MT 187 (Particle size analysis by laser diffraction)

Principles of method if other than guideline:

According to REACH Regulation (EC) No 1907/2006 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 the relevant Regulation (EC) No 440/2008. The international OECD 110 test guideline ‘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 document ‘Guidance on information requirements and Chemical SafetyAssessment-Chapter R.7a: Endpoint specific guidance’ stipulates that many methods are available for particle size measurements but none of them is applicable to the entire size range. ECHA’s guidance mentions the Laser scattering/diffraction as a method suitable for particles of all kind and makes reference to ISO 13320:2009.

GLP compliance:

yes (incl. QA statement)

Type of method:

Laser scattering/diffraction

Type of particle tested:

primary particle

Type of distribution:

volumetric distribution

Mass median aerodynamic diameter:

63.088 µm

Geometric standard deviation:

>= 2.594 - <= 2.649

Remarks on result:

other: The MMAD reported above is the mean of 5 measurements.

Key result

Percentile:

D10

Mean:

14.961 µm

St. dev.:

0.135

Remarks on result:

other: St.dev.= population standard deviation [µm]

Key result

Percentile:

D50

Mean:

53.51 µm

St. dev.:

0.473

Remarks on result:

other: St.dev.= population standard deviation [µm]

Key result

Percentile:

D90

Mean:

147.122 µm

St. dev.:

1.45

Remarks on result:

other: St.dev.= population standard deviation [µm]

No.:

#1

Size:

< 10 µm

Distribution:

5.26 %

No.:

#2

Size:

< 100 µm

Distribution:

77.95 %

Coefficient of variation for D50 is < 3% and for D10 and D90 < 5%; repeatability of the characteristic particles in the size distribution are within the acceptable limits as per the ISO 13320 standard.

Conclusions:

The particle size distribution of the substance was determined to be: D10= 15 µm, D50= 54 µm, D90= 147 µm and MMAD= 63 µm. 5.3% by volume was determined to be smaller than 10 µm. 78% by volume was determined to be smaller than 100 µm.

Executive summary:

The substance was visually observed to be made up of single crystalline particles. The particle size distribution of the substance was determined using laser diffraction analysis (dry powder module) in a GLP study according to ISO 13320 and CIPAC MT 187 to be: D10= 15 µm, D50= 54 µm, D90= 147 µm and MMAD= 63 µm. 5.3% by volume was determined to be smaller than 10 µm. 78% by volume was determined to be smaller than 100 µm.

Description of key information

The particle size distribution of the substance was determined using laser diffraction analysis (dry powder module) in a GLP study according to ISO 13320 and CIPAC MT 187 to be: D10= 15 µm, D50= 54 µm, D90= 147 µm and MMAD= 63 µm. 5.3% by volume was determined to be smaller than 10 µm. 78% by volume was determined to be smaller than 100 µm.