2.2.1 Partial Drying of Wet Samples >>

2.2 Two Step Total Dry Matter Determination of Wet Samples

For wet samples (less than approximately 85% dry matter) it is necessary to partially dry the sample in forced-air or microwave oven prior to grinding. The goal is to dry the unground sample while keeping sample temperature below 55 to 60oC so that chemical composition is affected minimally. Drying at low temperature (less than 60oC) does not remove all water from the sample; therefore (initial) partial drying does not represent the dry matter of the sample.

Following drying, the sample is ground and analyzed for (final) laboratory dry matter (the remaining 3 to 15% moisture) when other chemical constituents are determined.

Therefore, a two-step procedure for determining dry matter is recommended:
Step 1: Determine partial dry matter of sample (if less than 85% dry matter).
Step 2: Determine laboratory dry matter on ground sample and multiply partial dry matter times laboratory dry matter to determine total dry matter.

Step (1) may be skipped if dry matter ³85% and the sample can be ground without drying.

Drying method for a sample to be analyzed on NIR should be consistent with the drying method used for samples in calibration of the NIR.

2.2.1 Partial Drying of Wet Samples >>

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