Evaporators and evaporation systems are a key part of the sample prep process in many laboratories and industries. In particular, rotary evaporators have been crucial in materials, forensics, life science, environmental, and chemical industries for decades. In industry, evaporators are employed to improve the storage life of a product or to reduce its volume, as well as to remove water before drying. Rotary evaporators are made up of a vacuum source, collection flask, condenser, rotating flask, and a temperature bath. Dry evaporators, on the other hand, use a dry heat block instead of a bath to evaporate samples quickly under a gentle stream of nitrogen. Concentrators, as their name suggests, are used to concentrate samples and are particularly important in the water treatment and food and beverage industries.
Questions to Ask When Buying Rotary Evaporator
1.What are your sample sizes?
Microtiter plates and micro centrifuge tubes work best in a centrifugal vacuum concentrator. For large samples up to 450mls, a vortex evaporator is recommended.
2. What are your samples?
Acids require an acid resistant system. Solvents damage plastic and rubber components, an appropriate system to prevent damage is recommended. A -50C cold trap is ideal for aqueous based samples, a -85C cold trap traps most solvents and a -105C cold trap is recommended for alcohols.
3. Are your samples heat sensitive?
Even at ambient set point, vacuum concentrators add heat through friction. A concentrator that has refrigeration built into it will give you the temperature control recommended to maintain the viability of heat liable samples.
4.What safety features are available?
Due to the nature of heating up aqueous samples, acids, and solvents, a variety of safety accessories can be used to ensure the safety of the operators. As glassware is under extreme pressure due to the vacuum pump as well as being heated, coated glassware can be used to ensure flasks don’t shatter during operation. Shields and protective hoods with ventilation can also help ensure operator safety. Some manufacturers offer advanced options, such as motorized lifts and shutoff procedures for power outages or if the heating bath goes dry.
5.What environmentally friendly options are available?
For the condensing and collection of samples, many options exist. Condenser coils or cold fingers are generally paired with circulating tap water or dry ice. While these methods are adequate for the purpose, constant changing of water to prevent algae buildup can get wasteful, along with a constant need for dry ice. Many manufacturers now offer circulating chillers which can be attached to evaporators, allowing for highly efficient condensation without the waste associated with using tap water or dry ice.
Operators should make sure their rotary evaporator is designed and set up for the intended application. For example, if using acids, the system needs to be properly coated to protect the internal components and the pump from damage.