Not just another SOP story: How to program a rotary evaporator method

Performing routine methods and SOPs on your rotary evaporator is easiest if the method can be programmed, saved and run automatically. Programming an SOP might sound scary and off-putting, but it is not so bad. In this blog post, I walk you through the process of setting up a 4-step method on your rotary evaporation system, so you could save yourself time and trouble when performing SOPs repeatedly.

One of our neighbors has a six-month old baby and she invited my wife and me the other day to have lunch with them. The little one was just starting to eat solids, so it was very entertaining for us to watch her gobble down mashed carrot with such pure joy. Her mother was incredibly pleased that she had just bought herself a kitchen robot. She explained that she simply needs to program in a recipe, add all the ingredients to the bowl and out comes something yummy, for baby and for the rest.

Yes, I know some of you are rolling your eyes, especially those of you who like to get your hands dirty and cook up a storm. But there are a few standard, routine recipes where it would be nice to save time and energy and get to the result effortlessly.

I mean, the lab is the same, if you think about it. Sure, some experiments are wild and you want to really get into them and are excited about them. But there are also the repetitive, routine, standard methods, which are even appropriately called SOPs.

Not only would something like a programmable kitchen robot help you save time and energy when performing SOPs, really automating the process helps improve the reproducibility of it. When you program the method well, anyone who does it should end up with the same result. And isn’t that the point of SOPs?

Luckily, some rotary evaporators are a little bit like kitchen robots, if they come with some programmable parts. For example, the Rotavapor® R-300 comes with Interface I-300 Pro, where you can set up and save a method quickly and easily.

Different laboratories have various or even multiple SOPs for their rotary evaporators, depending on application and specific needs. But I’d like to walk you through an example SOP and how to program it so you can make your life easier.

Let’s take a method that is a bit more complex, for example an SOP with a gradient. This is an ideal method that would require programming, as without this, you would otherwise need to manually adjust system parts.

For example, you want to perform a rotary evaporation that starts at ambient pressure values and decreases to 100 mbar where it remains for a few minutes. Then you want to empty the receiving flask and finally dry the solvent.

If your rotary evaporator allows it, how can you go about programing this method?

First you need to think about how to divide the method into multiple distinct steps. In the above example, you could split up the method into four steps:

First step: gradient from ambient pressure to 100 mbar in 5 minutes
Second step: vacuum constant at 100 mbar for 15 minutes
Third step: empty the receiving flask and put it back
Fourth step: dry the remaining solvent with a vacuum at 10 mbar for 10 minutes and with the dry mode

You should be able to set this up on your interface, for example as below:

SOP, standard operating procedure, laboratory evaporation, rotavapor, rotary evaporator

Then you need to define each step, considering parameters such as:

Vacuum start – initial pressure value
Vacuum end – final pressure value
Timer – duration of the step
Rotation – rotation speed during step
Heating bath – heating temperature during step
Chiller – cooling temperature during step

SOP, rotary evaporator, interface, laboratory evaporation

For our example, step 1 can be defined with the above parameters.
But what do you do when a manual step needs to be involved? Ideally, your system lets you program this as well with options such as:

Remove collecting flask
Remove evaporating flask
Clean condenser
Attach bath cover
Clean system
Attach collecting flask
Attach dry collecting flask
Refill solvent
Transfer content to drying flask
Attach dry evaporating flask

In our example, we would select “Attach dry collecting flask” and the rotary evaporator would pause to give you enough time to perform this task.

In the last step, we’d like to dry the solvent. Here, we again have to select the values as per step 1 and 2. I would suggest using a pressure value such as 10 mbar or any pressure value that is. A rotation speed of 50 RPM, a heating bath temperature of 40°C, a cooling temperature of 0°C for a duration of 10 minutes should do the job just fine. If the option exists, you can also set up a rotation interval, for example of 10 seconds in one direction, then 10 seconds in the other direction. The rotation interval helps prevent the compound from sticking to the walls of the flask.

Save your method then and you’re good to go.

It’s as easy as getting a pizza dough out of a kitchen robot after all!
Do you want to see a visual demonstration of how to set up Interface I-300 Pro on Rotavapor R-300. Then be my guest with the following link:

And if one video isn’t enough for you, check out my birthday blog post where I recommend great clips on rotary evaporation. Surely, once you program your SOP, you will have all the time in the world to watch movies, rather than stand idly by your rotary evaporator! And I now have time to think of what else I will cook up for our next blog post. Feel free to leave me an idea in the comments section below!

Till next time,

The Signature of Bart Denoulet at Bart's Blog