Loss on Drying (LOD)

The Loss on Drying (LOD) test is a classic analytical technique used to determine the amount of volatile matter—including water and residual solvents—present in a sample. Unlike more specific tests (like Karl Fischer titration, which only measures water), LOD measures any mass lost when a sample is heated or dried under specific conditions.

Test Principle & Procedure

The principle is simple: Thermogravimetric analysis. You measure the mass of a sample before and after a drying process; the difference is the " Loss on Drying," typically expressed as a percentage.

Standard Procedure (e.g., USP<731>):

Applicable Industries

LOD is a foundational quality control test across several sectors:

• Pharmaceuticals: Ensuring active ingredients (APIs) and excipients meet stability and dosage standards.
• Food & Agriculture: Measuring moisture in grains, flour, and dried spices to prevent spoilage and ensure "fair weight" in trade.
• Chemicals: Testing polymers, resins, and fine chemicals for residual solvents.
• Cosmetics: Controlling the consistency and shelf-life of powders and creams.

Standards & Referencing Documents

Global regulatory bodies provide strict guidelines to ensure reproducibility: