3,5-dimethylpyrazole

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:

30 July 2012 to 05 September 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, with experiments conducted according to appropriate and valid guidelines and conducted under GLP conditions.

Qualifier:

according to guideline

Guideline:

other: Particle size analysis: CTL SOP No. 417

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: ISO 13320:2009

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: CIPAC MT 187

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

not applicable

GLP compliance:

yes (incl. QA statement)

Type of method:

Laser scattering/diffraction

Type of distribution:

volumetric distribution

Mass median aerodynamic diameter:

268.99 µm

Geometric standard deviation:

>= 1.482 - <= 1.486

Key result

Percentile:

D50

Mean:

251.932 µm

Remarks on result:

other: Average result is calculated from the entirety of data captured in each of the five runs and is not a simple arithmetic mean(migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.)

Key result

Percentile:

D10

Mean:

153.16 µm

St. dev.:

0.38

Key result

Percentile:

D50

Mean:

251.932 µm

St. dev.:

0.32

Key result

Percentile:

D90

Mean:

408.702 µm

St. dev.:

0.94

VISUAL MICROSCOPE OBSERVATIONS

- Standard visual observations: medium size, white powder with clusters.

- Observations at 100 x magnification: Particles appeared to be round edged crystals. The smallest individual particle was approximately 83 µm and the largest was approximately 432 µm.

- Observations at 400 x magnification: The test material was observed to be made up of single crystalline particles.

Table 1. Test Results (µm)

	Run 1	Run 2	Run 3	Run 4	Run 5	Average**
Volume weighted Mean	267.999	269.148	267.939	267.940	268.027	268.211
Median (d.50)	251.848	252.567	251.702	251.736	251.809	251.932
Mode (µm)	254.033	254.258	254.058	254.004	254.123	254.096
MMAD*	268.900	269.668	268.744	268.780	268.858	268.990
10% of material is <	153.355	153.801	152.730	152.980	152.944	153.160
50% of material is <	251.848	252.567	251.702	251.736	251.809	251.932
90% of material is <	407.819	410.528	408.539	408.202	408.453	408.702

*Mass median Aerodynamic Diameter

** Average result is calculated from the entirety of data captured in each run and is not a simple arithmetic mean.

0.0% by volume of sample was seen to be < 10.00 µm.

Table 2. Standard Deviation Results

Run No.	1	2	3	4	5	STDVP	% STDV
d10	153.355	153.801	152.730	152.980	152.944	0.38	0.25
d50	251.848	252.567	251.702	251.736	251.809	0.32	0.13
d90	407.819	410.528	408.539	408.202	408.453	0.94	0.23
d15.78	169.905	170.386	169.355	169.577	169.561	0.36	0.21
GSD*	1.482	1.482	1.486	1.484	1.485	0.00	0.10
MMAD	268.900	269.668	268.744	268.780	268.858	0.34	0.13

*Geometric standard deviation

Coefficient of variation: d50 < 3%; d10 and d90 < 5%. The repeatability of the characteristic particle in the size distribution is within the acceptability limits of the ISO 13320-1 test standards.

Conclusions:

Under the conditions of the test, the particle size of the test material was determined to have a MMAD (mass median aerodynamic diameter) of 268.990 µm, median diameter of 251.932 µm with a geometric standard deviation of between 1.482 and 1.486. The coefficient of variation was less than 3% at d50 and less than 5% for d10 and d90, thus the repeatability of the characteristic particles in the size distribution are within the acceptability limits of the ISO 13320-1 test standards.

Executive summary:

The particle size of the test material was determined by laser diffraction in a GLP study performed to the standardised guidelines Particle size analysis: CTL SOP No. 417, ISO 13320: 2009, CIPAC MT 187 and in consideration of the OECD guideline 110.

Under the conditions of the test, the particle size of the test material was determined to have a MMAD (mass median aerodynamic diameter) of 268.990 µm, median diameter of 251.932 µm with a geometric standard deviation of between 1.482 and 1.486. The coefficient of variation was less than 3% at d50 and less than 5% for d10 and d90, thus the repeatability of the characteristic particles in the size distribution are within the acceptability limits of the ISO 13320-1 test standards.

Description of key information

The particle size of 3,5-Dimethylpyrazole was determined in a key study (Livingston, 2012) to have a MMAD (mass median aerodynamic diameter) of 268.990 µm, median diameter of 251.932 µm with a geometric standard deviation of between 1.482 and 1.486. The study was performed to GLP and the standardised guidelines; particle size analysis: CTL SOP No. 417; ISO 13320: 2009; CIPAC MT 187 and in consideration of the OECD guideline 110.

Additional information

Livingston (2012) has been provided as the key study to address this endpoint, where the average particle size was determined by the laser diffraction method. The study was performed in line with GLP and standardised guidelines and had thus been assigned a reliability score of 1 using the principles for assessing data quality as set out in Klimisch (1997).