Preparation - Dry Matter - Humidity

The sample preparation steps are essential. They ensure the production of a homogeneous plant powder representative of the sample provided to the laboratory. The various operations performed on the sample must not alter it, such as through element loss or contamination.

If you wish to carry out these preparations yourself, USRAVE:

• advises you on which gloves to use for handling: Non-powdered vinyl (in french).
• warns you about potential contamination from grinders (in french).

Upon request, the laboratory offers:

• Counting: Determining the number of fruits, leaves, or needles in the sample.
• Washing: A process to remove surface contamination from the sample.

Samples arriving fresh at the laboratory undergo the following operations:

• Weighing: Weighing the entire sample, necessary for calculating concentration relative to the fresh matter.
• Drying: Removing water stored in the sample in climate-controlled chambers. The drying temperature varies depending on the volatility of the element to be analyzed (e.g., Hg, N, As, Se, and S are dried at 50°C). This step determines the dry matter content.
• Grinding: Reducing the previously dried samples to a powder. Non-contaminating grinders without loss are used (mesh size = 0.5mm).
• Homogenization: Mixing the plant powder to ensure that the test sample is representative of the sample you provided.
• Humidity: Measuring the sample's moisture content after grinding, storage, and homogenization. The moisture content is calculated after drying at 103°C ± 5°C

The prepared sample should ideally weigh ~10g.

For more information, feel free to contact us.

Crédit photos @A. Marquot