Prometryn

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: CIPAC method MT 187

Deviations:

no

GLP compliance:

no

Type of method:

Laser scattering/diffraction

Type of particle tested:

primary particle

Type of distribution:

volumetric distribution

Percentile:

D50

Mean:

24.8 µm

St. dev.:

0.1

Individual results of the three measurements

Measurement	Dv[10]	Dv[50]	Dv[90]
Run 1	6.88	24.7	157
Run 2	6.77	24.8	163
Run 3	6.73	24.9	172
Average	6.79	24.8	164
Stdev (%)	1.14	0.40	4.60

Conclusions:

The mean particle size distribution of the substance was determined to be 24.8 µm.

Executive summary:

The volumetric particle size distribution of the substance was determined with a laser diffraction method to CIPAC method MT 187, using a water dispersion unit. The test substance was added to the water dispersion unit of the instrument and the diffraction pattern of a laser beam passed through the dispersion measured at ambient temperature. The laser diffraction study can be conducted in water for very insoluble substances with solubility of less than 10^-6 g/L (according to OECD test guideline). The test substance has a solubility of 0.033 g/L at 25 °C, which is above the required solubility threshold. To minimise the impact of dissolution, the particle size was measured immediately after the test substance was added to the water. The relative standard deviations of the particle size distribution for the Dv[10], Dv[50] and Dv[90] values were calculated to be 1.14, 0.40 and 4.60% indicating that the impact of water solubility on the particle size distribution determination was less than 5%. The results obtained from three measurements thus were considered as reliable: 

Dv[10] = 6.79 µm

Dv[50] = 24.8 µm

Dv[90] = 164 µm

Description of key information

The particle size distribution of a representative sample of substance was determined by a laser diffraction method. The median particle size of the distribution was determined to be 24.8 µm, with a relative standard deviation of 0.40%.