A rotating evaporator is a tool used to remove moisture from liquids in laboratories for the delicate and effective evaporation of solvents from samples. An illustration of a conventional rotary evaporator may be seen on the right.


How to Use Rotary Evaporators Safely?


  1. When using the equipment, put on lab coats, proper gloves, closed-toed shoes, and eye protection (safety glasses or goggles).
  2. To prevent tangles, tie back long hair and do not wear loose clothing.
  3. Ensure that the equipment is kept in good functioning condition. Periodically inspect seals and replace them if necessary. Leaking and a decrease in vacuum are typically signs that seals need to be replaced.
  4. Make use of a vacuum source that is suitable for the required level of vacuum. Diaphragm pumps are suitable for the majority of applications. High vacuum levels are produced by belt pumps and rotary vane pumps, which can lead to excessive bumping (flash boiling of the solvent, for example) and clog traps. Water aspirators shouldn’t be used.clog traps, etc. It is not advisable to use water aspirators since they can let solvent vapours enter drains and waste a lot of water.
  1. Before using any glassware, inspect it for any obvious chips, cracks, or scratches. Always handle glasses with care.
  2. Place a cold trap between the pump and the rotovap at all times. Never use liquid nitrogen to cool the trap because doing so can lead to liquid oxygen condensation. Each time the trap is used, empty it. If a trap becomes clogged, it must be disconnected, opened to the atmosphere, and the vacuum must be turned off right away to prevent an explosion. In a fume hood, let the trap defrost and empty.
  3. Use a cold bath to chill the receiving flask (usually ice water) and make sure the liquid used to cool the condenser is the right temperature for the solvent being extracted. This will encourage effective solvent collection and prevent cold traps from becoming overloaded. To prevent water waste, supply the condenser with cooling fluid using chilled recirculators or similar devices.
  4. To prevent contamination of the condenser region (and your sample) in the event of bumping, use a bump bulb (see image) placed between your sample and the condenser. After each usage, remove the bump bulb from the rotovap and clean it well to avoid ground glass joint connections sticking together and to shield upcoming samples from contamination.
  5. Whenever possible, use clamps or Keck clips to fasten flasks, bump bulbs, and ground glass joint connections to the apparatus.
  6. Always keep residues and organic solvents away from electrical parts and water baths. Replace any contaminated tubs at away.
  7. Be familiar with the dangers and characteristics of the compounds you are using. Rotovaping of hazardous materials ought to only be done with the proper local exhaust (in a fume hood, or occasionally, with a snorkel exhaust). If you have any concerns about the suitability of your rotovap configuration for your application.
  8. Materials that are sensitive to air and water cannot be utilised with rotovaps. Additionally, rotating highly reactive materials is not advised.
  9. Materials that are sensitive to air and water cannot be utilised with rotovaps. To avoid harming seals, highly reactive materials shouldn’t be rotovaped either. For these goods, distillation is a better option for solvent removal.
  10. The solvent’s boiling point should not be exceeded by the water bath temperature.
  11. 1 To prevent bumping, set the motor to start rotating slowly before adding vacuum.

Once the vacuum is activated, alter the spinning speed to increase surface area and avoid bumping.

16. Adjust the pressure to the bare minimum required for effective solvent removal. Some units have mechanisms that automatically regulate the pressure to a predetermined set point. For some devices, the vent stopcock is found at the top of the condenser and must be used to manually regulate pressure. To prevent bumping, the pressure for both kinds of units should be watched carefully and adjusted as appropriate.

17. In order to prevent unintentional mixing of incompatible materials or unknown substances, always empty the solvent collection flask of the device right away after usage.

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