201.51b—Purity procedures for coated seed.
(a)
The working sample for coated seed is obtained as described in § 201.46(d) (1) and (2), and weighed in grams to four significant figures.
(b)
Any loose coating material shall be sieved, weighed, and included with the inert matter component.
(c)
Coating material is removed from the seed by washing with water or other solvents such as, but not limited to, dilute sodium hydroxide (NaOH). Use of fine mesh sieves is recommended for this procedure, and stirring or shaking the coated units may be necessary to obtain de-coated seed.
(d)
Spread de-coated seed on blotters or filter paper in a shallow container. Air dry overnight at room temperature.
(f)
The de-coated seed shall be separated into four components in accordance with §§ 201.48 through 201.51. §§ 201.51a (a) and (b) shall not be followed. The weight of the coating material is determined by subtracting the sum of the weights of the other four components from the original weight of the working sample. The percentage of coating material shall be included with the inert matter percentage. Calculate percentages of all components based on the original weight of the working sample (see paragraph (a) of this section).