Desiccator Guide

Maintaining the integrity of sensitive samples and chemicals is imperative in any laboratory setting. Many elements put these samples at risk for degradation — including uncontrolled moisture.

Desiccators protect these delicate substances by providing a dry environment and preventing contamination caused by moisture. The definition of a desiccator is an air-tight chamber that uses various drying agents, called desiccants, to cool and dry heated samples and keep them dust-free in a low-humidity atmosphere.

A desiccator is essential for protecting hygroscopic materials that tend to attract and absorb moisture in the natural environment.

What Are the Common Types of Desiccators?

Here are the desiccator types commonly used in laboratory settings.

1. Standard Desiccators

Standard desiccators, often constructed of stainless steel and glass, require manual operation and monitoring. These user-friendly desiccators dry samples under vacuum pressure and are generally capable of using any desiccant, which must be regenerated by heat or replaced as needed. Standard desiccators are portable and tend to be more cost-effective compared to other types.

2. Powered or Automated Desiccators

Automatic or powered desiccators can continuously regenerate the desiccant as needed using electronic mechanisms. Electric fans and heaters prevent desiccants from becoming saturated, enabling many regeneration cycles.

These types of desiccators offer precise humidity control to protect sensitive samples. They also operate on a set schedule, meaning minimal monitoring is required. Powered desiccators offer quick moisture removal and feature a door-mounted hygrometer for easy reading.

3. Static Free Desiccators

Certain instruments, objects and chemicals may be sensitive to electrostatic charges. Unlike plastic desiccators, static-free desiccators are constructed of durable stainless steel and glass to prevent static buildup and promote static-free drying.

Additionally, static-free desiccators feature vapor-deposited tin oxide film to protect against static discharge when indoor humidity levels are low. This means you can effectively remove moisture from static samples without worry of warping and discoloring that tends to occur with conventional plastic desiccators.

What Are Desiccators Used For?

While the exact use of a desiccator depends on the specific substance or object, these sealable enclosures play a critical role in a variety of laboratory applications:

• Cooling heated objects
• Drying biological specimens 
• Protecting samples from atmospheric moisture, dust and humidity
• Storing reagents, soil samples, raw materials and IR cells
• Removing moisture from chemical substances
• Drying bacteria and proteins
• Cooling and storing standard solutions like sodium chloride and potassium chloride
• Stabilizing temperatures for materials that require frequent weighing
• Transporting or storing samples for short or long-term

Desiccators are also used for many instances where accurate chemical measurements are required before a chemical reaction.

What Type of Desiccants Can Be Used in a Desiccator?

A desiccant is a drying agent added to the lab desiccator to induce or sustain dryness and prevent moisture damage to sensitive samples. Desiccants do the heavy lifting in the process of desiccation. 

Each desiccant has unique properties that impact desiccation performance, so it's important to understand their characteristics. Commonly used desiccants include:

• Silica gel: Also known as silicon dioxide, a naturally occurring mineral, silica gel is the only FDA-approved desiccant, making it suitable for direct contact with items in the pharmaceutical and food industries. This is a popular desiccant option because it is non-toxic, non-flammable and water-insoluable. Silica gel can sometimes be reusable if heated to the right temperature. 
• Molecular sieves: This synthetic crystalline aluminosilicate desiccant, also known as synthetic zeolite, is typically used for biochemical packaging and reagants and can be tailored to absorb molecules of a specific size. Molecular sieves are among the most effective desiccants because they attract and retain particular substances. 
• Activated alumina: This desiccant is a highly porous material that performs similarly to silica gel. Activated alumina has a high surface area-to-mass ratio and works through adsorption, trapping moisture and impurities in the air while maintaining a dry environment. 

FAQs About Desiccators and Desiccants

You can optimize your storage conditions by selecting the right desiccator size, shape and control mechanism for your laboratory samples. We've highlighted some common questions you may have to help you narrow down your options.

1. How Do I Choose the Right Desiccator for My Laboratory?

The right desiccator will depend on your unique laboratory needs, applications and space requirements. Here are some questions to ask yourself when buying a desiccator:

• What type of desiccator best suits the type of samples in my laboratory?
• Does my staff have the bandwidth to manually monitor the desiccator?
• How many samples will I need to protect from moisture and contamination?
• Will my samples already be dry, or do they need to be dried before they're placed in the desiccator? 
• Is static discharge a concern for my samples?
• What is the general size of the items I need to store? 
• Where will I house the desiccator?
• Do I need a desiccator that can be stacked?
• Will I require adjustable shelves for easier accessibility and additional storage?
• How fast do I need my desiccator to dry my samples?
• Do I want humidity control features?
• Does my lab require a portable desiccator?

2. How Do I Properly Use and Maintain a Desiccator?

As with any laboratory process, desiccators require appropriate use and maintenance for sealing, storing and handling samples. Lab staff members should keep the desiccator closed unless samples are actively being placed or removed. Because desiccators are designed to maintain dryness, unnecessary opening and closing can create contact with atmospheric moisture.

Here are some tips for maintaining a proper, airtight seal and protecting the integrity of your samples and materials:

• Correctly label specimens and samples.
• Group similar items together in the appropriate environment.
• Use non-flammable desiccants.
• Keep non-flammable desiccants in a cool, dry area and avoid exposure to heat and sunlight.
• Use caution when opening and closing the lab desiccator door.
• Follow safety precautions when handling hygroscopic chemicals.
• Adhere to desiccator instructions provided by the manufacture.
• Monitor desiccant regularly to ensure its effectiveness.
• Change desiccant as needed.

3. How Long Do Desiccators and Desiccants Last?

Desiccator cabinets generally have a much longer life span when constructed with durable materials, including stainless steel and glass. Plastic and acrylic desiccators tend to deteriorate and erode faster after chemical exposure. Stainless steel desiccators also offer enhanced seal integrity and are easier to clean, contributing to a contamination-free environment.

The life span of desiccants depends on many factors, including:

• Humidity levels
• Storage temperatures and conditions
• Desiccant packaging design material
• Desiccant size and composition 

Desiccants do not always have a set expiration date — they have a general shelf life of several months to a couple of years. You may use an indicator on some desiccants, like silica gel bags, that change color when they become saturated. The color change will occur when the desiccant needs to be regenerated or replaced. Regular desiccant inspections are ideal for detecting signs of physical deterioration or leakage.

Contact Boekel Scientific for High-Quality Desiccators

A wealth of factors can influence the effectiveness and integrity of your desiccator. To ensure quality and efficiency, it's important to find the right equipment for your lab's specific needs. At Boekel Scientific, we're committed to designing innovative lab equipment and delivering superior customer service to the scientific and healthcare communities. 

We carry standard, automatic and static-free desiccators in various sizes, featuring one-piece neoprene door gaskets for airless security. We encourage you to browse our desiccators or contact us to learn more about our equipment.