Desiccators

A desiccator is a sealed container used to remove moisture from substances or to keep items dry. In laboratory settings, desiccators protect hygroscopic reagents, dried glassware, and other moisture-sensitive materials by isolating them from ambient humidity. They are also used to dry solids or to store dehydrated materials.

Most desiccators consist of two parts: a base that holds a desiccant and a raised perforated shelf, and a tight-fitting lid. The desiccant chamber is filled with drying agents such as silica gel, calcium chloride, activated alumina, or molecular sieves. A small pedestal supports the items above the desiccant to prevent direct contact. Some models include a stopcock or valve to connect to a vacuum source, enabling faster drying or an inert, moisture-free environment.

Operation is simple: items are placed on the pedestal inside the chamber, the lid is closed, and the desiccant absorbs water vapor from the air inside, lowering humidity. Drying times vary with the desiccant and the material. When the desiccant becomes saturated, it is regenerated by heating or replaced with fresh material.

Common uses include storing moisture-sensitive chemicals (for example, certain organometallic reagents), drying glassware before use, and preparing samples for accurate weighing or analysis. Safety considerations include avoiding contact between desiccants and reagents that may react with them and following manufacturer guidance when regenerating or disposing of spent desiccants. Vacuum desiccators may be employed to accelerate drying or maintain very low humidity.