4.1 Preparation Method A—Method suitable for the preparation of large quantities (>20 g) of field collected samples into a form appropriate for compositional analysis. Woody samples must first be available as chips of a nominal 5 by 5 by 0.6 cm (2 by 2 by ¹/₄  in.) or less and twigs not exceeding 0.6 cm (¹/₄ in.) diameter. Herbaceous materials may be processed as whole straw. It is recommended that wastepaper should be shredded into pieces less then 1 cm (¹/₂ in.) wide. Furthermore, it is recommended that twigs, straw and wastepaper should not exceed 61 cm (24 in.) in length to facilitate handling.

4.2 Preparation Methods B and C—Test methods are suitable for very moist feedstocks, samples that would not be stable during prolonged exposure to ambient conditions, or for drying materials when room conditions deviate from the ambient conditions described in 3.1.1. These test methods are also suitable for handling small samples of biomass (<20 g). The drying step is done in a convection oven at 45°C (Test Method B) or by lyophilization (Test Method C).

4.3 This practice is not intended for materials that will already pass through a 20 mesh sieve or cannot be dried by the described methods to a total solids content of greater then 85 %, based on an oven dried weight.

4.4 This practice will separate the milled material into two fractions, a −20/+80 mesh fraction and a −80 mesh fraction.

4.4.1 Extraneous inorganic materials will accumulate in the -80 mesh fraction and it should be analyzed independently from the -20/+80 mesh fraction. Weighted results from the two fractions can then be combined to obtain results for materials on an "as received" basis.

Note 1: During analysis, the very fine consistency of the -80 mesh fraction may cause problems in filtering operations and should be handled appropriately.

1.1 This practice covers a reproducible way to convert hardwoods, softwoods, herbaceous materials (such as switchgrass and sericea), agricultural residues (such as corn stover, wheat straw, and bagasse), wastepaper (such as office waste, boxboard, and newsprint), feedstocks pretreated to improve suitability for fermentation and fermentation residues into a uniform material suitable for compositional analysis.

1.2 Milling and sieving actions both produce large amounts of dust. This dust can be a nuisance hazard and irritant. Use appropriate respiratory protection as needed. If excessive amounts of dust are allowed to become airborne a potential explosion hazard is possible. Provide appropriate dust control measures as needed.

1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.