Purity Analysis Section

The Colorado Seed Laboratory is an official AOSA laboratory, but we also perform tests according to ISTA and Canadian standards.  The primary reason for having rules regarding seed testing is consistency.  It should be possible to replicate the results of a viability test in Colorado in Maine, and vice-versa.

	A purity analysis test consists of separating the sample into four components: pure seed, other crop, weed, and inert material.
The submitted sample is divided into a working sub-sample consisting of roughly 2,500 seeds.  We use a divider to indiscriminately select the seeds that we will test.  There are many types of dividers: pictured here is an electric Gamet divider, the most widely used.
	The seed analyst, using a microscope or a magnifying lamp (depending on the seed size), then separates the sample into the four components.  Each component is weighed and a percentage is derived.  Pictured here is a typical workstation, with a microscope, blower, and purity table.
A seed blower separates based on density, and is used for removing chaff, empty seeds, or other contaminants.
	Weeds and other crop must be identified and noted on the report.  The lab uses a variety of texts, SeedImages.com and our seed herbarium to ID contaminants.  Pictured here is one of the lab's herbariums.

If you have further questions please contact us.