ethametsulfuron-methyl (ISO); methyl 2-[(4-ethoxy-6-methylamino-1,3,5-triazin-2-yl)carbamoylsulfamoyl]benzoate

Particle size distribution (Granulometry)

Administrative data

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:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Materials and methods

Test guideline

Test guideline 1

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:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7520 (Particle Size, Fiber Length, and Diameter Distribution)

Deviations:

no

GLP compliance:

yes

Type of method:

sieving

Type of particle tested:

primary particle

Type of distribution:

mass based distribution

Test material

Test material information

Constituent 1

Reference substance name:

Reference substance 002

Cas Number:

97780-06-8

Test material form:

solid

Details on test material:

- Purity: 98.7%

Specific details on test material used for the study:

Prior to analysis, the test material was thoroughly mixed via rotation and inversion. Each empty sieve was weighed using a calibrated/verified balance; the weights were recorded. Approximately 180 milligrams of the test substance was weighed into a tared beaker. Initially the dust fraction was removed by first pouring the weighed sample into a 20 micron sieve (with a collection pan underneath), covering the sieve and manually shaking several times. The dust fraction residing in the collection pan was weighed and then discarded, if applicable.
Eleven sieves ranging in size from 20 to 710 microns with a collection pan under the 20 micron sieve were assembled. The sieved test sample, now residing in the 20 micron sieve (after dust fraction removal) was placed into the top sieve (710 micron). The entire sieve stack was placed on a Gilson Model SS-3 shaker; the sieve time set for five minutes at an amplitude setting of five. After the timed shaking interval, the sieves were removed from the shaker, tapped to reposition the test material inside the sieve stack and placed back on the shaker for an additional sieve cycle. The sample weight of each sieve, containing test material, was recorded. The weight percent of each fraction was calculated by dividing the weight of material retained on each sieve (g) by the original subsample weight (g). The total percentage mass recovered was calculated by adding the weight retained from all sieve fractions divided by the original subsample weight. The testing method was repeated using another separate sub-sample.

Results and discussion

Particle size distribution at different passages

Particle size distribution at different passages 1

No.:

#1

Size:

>= 250 µm

Distribution:

87 %

Particle size distribution at different passages 2

No.:

#2

Size:

<= 250 µm

Distribution:

12 %

Particle size distribution at different passages 3

No.:

#3

Size:

<= 20 µm

Distribution:

< 0.1 %

Any other information on results incl. tables

The test material subsample masses used were 0.1790 and 0.1846 grams. No sieve clogging or static issues were observed at any point during the testing. The average amount of particulate matter either at or larger than 250 microns in the test substance was approximately 87%. The average amount of particulate matter smaller than 250 microns in the test substance was approximately 12%. The particle size distribution dramatically dropped off below 63 microns. The average amount of particulate matter smaller than 20.0 microns in the test substance was negligible. The mean weight percent recovery for the two analyses was 98.3%. The sieve testing for the test substance provided the following mean particle size distribution:

 

Sieve Size (µm)	^1Mean Percentage Particles Recovered
710	11.5
500	22.2
355	30.8
250	22.3
180	7.6
125	2.6
90	0.9
63	0.4
45	<0.1
32	<0.1
20	<0.1
<20	<0.1
Total Mean % Mass Recovered = 98.3
^1Generated using Microsoft Excel 2010 in full precision mode. Manual calculations may vary slightly.

Applicant's summary and conclusion

Conclusions:

87% of particulate matter was ≥250 µm
12% of particlulate matter was ≤250 µm
Negligible amount of particlulate matter was ≤20 µm

Executive summary:

The particle size distribution of the test substance was determined according to OECD Guideline 110. The white powdery test material was observed to be semi-clumpy by the analyst. The average amount of particulate matter either at or larger than 250 microns in the test substance was approximately 87%. The average amount of particulate matter smaller than 250 microns in the test substance was approximately 12%. The average amount of particulate matter smaller than 20.0 microns in the test substance was negligible. The mean weight percent recovery for the two analyses was 98.3%.