Desiccator – A Quality control Laboratory Device
This article contains information about Desiccator – A Quality control Laboratory Device which is used in the Quality control laboratory used to maintain the dryness of samples by removing moisture from an enclosed space.
Desiccator – A Quality control Laboratory Device
A desiccator is an essential laboratory device used to maintain the dryness of samples by removing moisture from an enclosed space. This is achieved using a drying agent, commonly silica gel, which adsorbs humidity from the air inside the desiccator.
Components of a Desiccator :
1. Body of the Desiccator :
• Typically made of glass or transparent plastic with an airtight seal.
• Equipped with a tight-fitting lid to prevent moisture from entering.
• Contains a desiccant (silica gel) to adsorb humidity and maintain a dry environment.
2. Stopcock (Vacuum Valve) – Optional
• Some desiccators include a stopcock to control the internal pressure.
• It is used to create a vacuum, which enhances drying efficiency and prevents oxidation.
3. Porous Plate :
• A perforated ceramic or plastic plate inside the desiccator.
• Supports the samples and prevents direct contact between the desiccant and stored materials.
4. Desiccant (Silica Gel) :
• The primary drying material responsible for moisture adsorption (not absorption).
• Prevents sample deterioration by keeping the internal atmosphere dry.
• Often contains a color indicator to signal when it is saturated with moisture.
How Silica Gel Works in a Desiccator :
Silica gel adsorbs moisture from the air, preventing water molecules from affecting stored samples. It is widely used in laboratories and industrial applications to preserve materials, prevent degradation, and control humidity levels.
How to Identify Expired Silica Gel? :
Silica gel often contains a color indicator that changes when it has adsorbed moisture and needs replacement:
• Blue silica gel → Turns pink or colorless when saturated.
• Orange silica gel → Turns green when it can no longer adsorb moisture.
• Yellow silica gel → Darkens to green or black after moisture adsorption.
Some types of silica gel do not contain a color indicator, requiring regular replacement based on usage time.
How to Regenerating Silica Gel for Reuse :
If silica gel adsorbs too much moisture, it loses its drying efficiency. However, it can be recharged and reused by heating it in an oven under controlled conditions:
• Temperature Range: 85–150°C (Avoid exceeding 200°C, as high heat can damage the porous structure).
• Time: 1 to 2 hours, depending on the amount of moisture adsorbed.
• Cooling Process: Allow the silica gel to cool inside a dry, sealed container before use. This prevents it from immediately reabsorbing moisture from the surrounding air.
