What are the official methods of moisture content determination
Methods for Moisture Content Determination
Several official methods are used to determine the moisture content of a substance:
- Karl Fischer Titration: This chemical titration method is highly accurate and is used for a wide range of materials, including pharmaceuticals, foods, and chemicals.
- Oven Drying: The sample is dried in an oven at a controlled temperature to remove moisture. The difference in weight before and after drying determines the moisture content.
- Microwave Oven Drying: Microwave drying is a rapid method that uses microwave energy to remove moisture from a sample. The weight loss is used to calculate the moisture content.
- Calcium Hydride Reaction: The sample is reacted with calcium hydride to produce hydrogen gas. The volume of hydrogen produced is then used to determine the moisture content.
- Distillation Method: The sample is heated in a distillation apparatus, and the moisture is condensed and collected. The volume of distilled liquid is used to calculate the moisture content.
- Gas Chromatography: The sample is injected into a gas chromatograph, where the moisture is separated and quantified based on its physical properties.
The choice of method depends on the accuracy required, the type of material being tested, and the availability of equipment.