Four rotary evaporation tricks to keep your safety standards high

Well, if there is one message that is worth repeating, it is that safety comes first! No matter what technique you are using in lab, you should up your safety standards to the highest level to protect not only yourself, but your samples as well. Since I’ve already discussed safety measures for your purifications, today I turn to rotary evaporation and give you four hints on how to optimize the safety of your distillations.

I was on the phone with a former colleague the other day. We were telling stories from the good old lab days and laughing heartedly. At one point, he recalled the worst accident he had in the lab. It was late Friday afternoon, and it was his daughter’s birthday. He was rushing to finish off an experiment with radioactivity. In his hurry, he dropped several petri dishes with radioactive S-35 he was using to label proteins in his cells. Well…he was pretty late for the birthday party after all.

While we can laugh about it now, it made me think how complacent we can become in the lab. We often forego precautions, safety measures, because we feel confident, are in a rush, or don’t feel the need to maintain certain safety standards.

But this is so bad! Not just for us, the environment, but also for our samples! I am such a fan of safety, I’ve already written two posts on safety in chromatography.

So I’ve decided to dedicate this post to safety standards in one of the most frequently used methods in the synthesis lab, rotary evaporation. I mean, the more often you use it, the most likely you are to cut some corners when it comes to safety. But I am here to remind you. The more often you use it, the higher the chances are that you get yourself into some trouble as well.

So enough blabbing, let’s get started, as I highlight four accessories that can improve the safety standards of your routine rotary evaporation tasks!

1. Use flasks/condenser with plastic coating for user and sample safety

Flasks and condensers are typically made of borosilicate glass. But if you are concerned about safety standards or work with expensive samples, you should consider obtaining plastic-coated glassware. For example, you could also have flasks made of glass with plastic coating for working temperatures between 40°C to 60°C or for lower temperatures between -70°C and 40°C for cold track applications. The benefits of glassware with plastic coating include:

  • In case of implosions or hard impact, the chemicals inside your flask, or inside the condenser, will not just fly out towards you
  • You obtain more sturdiness in case someone or something bangs against your flask
  • More sample safety as you retain your sample within the evaporating flask, so even if your evaporating flask drops, you can still recover your sample

2. Install a secondary condenser to eliminate emissions

Secondary condensers, which you mount onto the vacuum pump, can come in various types. Some have coils inside, others are so made to be suitable for use with dry ice. Regardless, all secondary condensers serve the same purpose: they prevent emissions into the atmosphere by ensuring all solvent vapor is condensed and collected in the receiving flask. If the conditions you are working under are too harsh, the condenser of your rotary evaporation is operating at maximal capacity. This results in solvents traveling through the pump, hence the need for a secondary condenser. Ultimately, by reducing harmful emissions, you improve the safety standards of your lab.

3. Put in splash shields or protection shields to avoid splashes

Enclose your evaporating flask with a splash shield or a protection shield to avoid distillation splashes. The main difference between the two accessories is that you must open the splash shield to remove your flask from the rotary evaporator. In those few seconds, you are left unprotected. See an image of a protection shield (left) and a splash shield (right).

4. Use a level sensor to prevent overflow

Curious what this accessory can do your safety standards? Simply, attach it to the receiving flask of the secondary condenser or the actual rotary evaporator. The level sensor detects when the receiving flask has passed the maximal fill level, so you receive a warning message on the interface of your system that the collection flask needs to be emptied.

You want to see some of these rotary evaporators in action? My colleagues just put together a wonderful webinar on purification and concentration of vitamins, which is now available on-demand. There is not only a theoretical, but a lab component, so make sure you check it out.

What do you think about these ways of improving safety standards during rotary evaporation? Have I missed any that you regularly rely on? Let me know in the comments below. Until then, slow and steady wins the race! Don’t rush, stay safe!

Till next time,

The Signature of Bart Denoulet at Bart's Blog