1H-1,2,4-triazole, sodium salt

Particle size distribution (Granulometry)

Description of key information

Samples from three manufacturers were initially assessed by sieving with a 100 µm sieve.   The sample from Arkema showed virtually no particles <100 µm, so in accordance with the integrated testing strategy for granulometry, no further testing was carried out on that sample.  The sample from DSM was shown to comprise particles that were mostly (84.7%) <100 µm, but further analysis using a cascade impactor showed that relatively few of them were <10.0 µm (<= 3.60%) and <5.5 µm (<= 1.25%).  The sample from Saltigo passed 31.1% through the 100 µm sieve, but subsequent analysis by scanning electron microscopy showed that the particles had high aspect ratios such that their mean diameters were mostly (81.77% to 91.99%) >100 µm, with relatively few (8.01% to 12.23%) 10-100 µm, and essentially nothing smaller.

Additional information

A sample of the substance from Arkema was sieved for ~30 minutes on an Inclyno sieve shaker using a 100µm sieve. The mass passing through the sieve was found to be only 0.398%, so the substance was concluded to be essentially non-inhalable and, in accordance with the integrated testing strategy for granulometry,no further testing was carried out.

A sample of the substance from DSM was sieved for ~30 minutes on an Inclyno sieve shaker using a 100µm sieve. The mass passing through the sieve was found to be 84.7%, so further testing was carried out using a 5-stage cascade impactor with cut-point aerodynamic diameters of 10.0, 5.5, 2.4, 1.61 and 0.307 µm, with the following results.

Run No.	% < 0.307 µm	Cumulative % < 1.61 µm	Cumulative % < 2.4 µm	Cumulative % < 5.5 µm	Cumulative % < 10.0 µm
1	0.183	0.309	0.562	1.25	3.60
2	0.108	0.180	0.334	0.737	2.23
3	0.125	0.177	0.315	0.611	1.91

Too few particles were of a size less than 10.0 µm to allow accurate assessment of mass median aerodynamic diameter (MMAD).

A sample of the substance from Saltigo was sieved using a 100µm sieve, and the fraction passing through (31.1%) was analysed by scanning electron microscopy (SEM) with the following results.

Counts	1101
	Mean Diameter	Aspect Ratio
Minimum	9.79 µm	1.04
Maximum	275.66 µm	3.98
Arithmetic mean	116.79 µm	1.48
Median	114.52 µm	1.37
Standard deviation	35.08 µm	0.38

SEM analysis showed that the particles possessed aspect ratios of 1.04 to 3.98, and that majority of them actually had mean diameters >100 µm, such that overall, the composition of the substance was 81.77% to 91.99% >100 µm, 8.01% to 12.23% 10-100 µm, and 0.00% (0.00002% to 0.00004%) 4-10 µm in diameter.