Desiccators are the sealable enclosures that have desiccants that are used for preserving the moisture-sensitive elements like as cobalt chloride paper for specialized use. Mostly, the desiccators are used to protect the chemicals that are either hygroscopic or possess the ability to react with humidity present in the atmosphere.
The elements of the desiccators come in contact to atmospheric moisture if the desiccators are opened. It also needs some time to reach at a low humidity. Therefore, these are not suitable for preserving chemicals that can rapidly or violently react with the atmospheric moisture. These chemicals include the alkali metals, for which a glovebox or Schlenk-type apparatus should be used. Desiccators are often seen in the applications where the traces of water are to be eliminated from an almost-dry sample.
The Desiccator’s Constituents
The lower section of the desiccator has freshly calcined quicklime, lumps of silica gel, and Drierite or anhydrous calcium chloride that absorbs water vapor. The substance for which desiccation is needed, is put in the upper section, usually on a perforated and glazed ceramic plate. The ground-glass rim of the desiccator lid should be greased via fine layer of vacuum grease or any other lubricant to make an airtight seal. To prevent any damage to a desiccator, always slid the lid carefully instead of directly placing onto the base.
The Operations of Desiccators
In laboratory use, the most common desiccators are usually circular and made of heavy glass. There is typically a removable platform where the items are stored and placed. The desiccant, an otherwise-inert solid like silica gel, fills the space under a platform. Color changing silica might be used to specify when it should be refreshed. Indication gels stereo-typically change from blue to pink once they absorb moisture but other colors might be used.