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Rotary evaporator on a lab bench
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Innovative Features of Evaporators

Tapping on new features of evaporators can boost research productivity

Andy Tay, PhD

There are three main uses of evaporators in the lab. Most typical evaporators, except evaporator concentrators, apply heat directly to the sample with a heating block (called dry evaporator) or water bath (called wet evaporator) while maintaining a vortex motion to continuously mix the sample and increase surface area to boost evaporation. They can help remove water or organic solvents to concentrate the samples, recycle solvents, or separate solvents. 

Rotary evaporators are typically used to remove low boiling organic solvents. With vacuum, they can further reduce the boiling point of solvents to accelerate evaporation under reduced pressure. Another common evaporator uses nitrogen gas, which enhances the rate of evaporation by blowing nitrogen across the sample surface. Evaporators are used extensively in the pharmaceutical industry, toxicology, and environmental testing for sample purification and analyses. Here, we highlight innovations in evaporators to enhance your research productivity. 

Dual functions

Not all commercially available evaporators can both evaporate and concentrate. For separation purposes, samples can be heated directly to remove solvents. If the sample is not heat sensitive, it can be concentrated using direct heat. However, for biological materials that can be denatured by heat, such as peptides and nucleic acids, there are evaporator concentrators that instead generate centripetal motion within the sample tube to evaporate the solvent. Although this process is more time consuming, it protects the biological activity of the analyte. 

Heating rate

Manufacturers have introduced digital controllers to manage heating and rate of temperature change. This is helpful to prevent overheating and maintain constant temperature to optimize evaporation rate. Another innovative feature is fast termination of heating after the set end point is achieved. This is important because operators need time to remove samples or perform additional procedures, but if there is still heat transfer, evaporation does not stop and the sample might dry out. This may be problematic for samples where a small amount of solvent is needed to maintain structural integrity and bioactivity.

Throughput

While wet evaporators can handle larger sample volumes than dry evaporators, the former is unable to work on multiple samples simultaneously. Innovation in dry evaporators has enabled as many as 100 samples to be processed concurrently. This can be helpful for labs with high throughput needs, especially when they are trying to optimize a chemical synthesis process and require concentrated analytes for downstream analysis. 

User interface

A good user interface is important so that users can easily and accurately regulate heating rate and pressure. Older evaporators do not offer digital interfaces, so users must manually adjust parameters. Newer models of evaporators, on the other hand, are equipped with digital user interfaces that display vortex speed, heating block temperature, time, and vacuum levels. They also have alarms to notify users when the process is near completion or completed. Users can also save programs for easy recall and protocol modifications.

In conclusion, evaporators are an important tool to concentrate and purify samples. In response to users’ feedback and needs, manufacturers have innovated to improve biological activity, throughput, user experience, and safety while using evaporators to boost research productivity.