Yesterday an old argument reemerged in the lab. On discussing the use of an auto-column and the ways in which we can implement it in the lab and the ways in which time will be saved one of us mentioned that an auto-column MPLC would never be as good as a good ol' hand worked flash column.
Well, this discussion, I am sure, has been brought up in a number of scientific circles since the emergence of these new-fangled contraptions. Most notably, the Biotage Isolera (Image 1) and the Teledyne CombiFlash (Image 2) as well as the Kyle Finchsigmate's MPLC for the people (Image 3). But, are they as good as the good ol' hand column.
Well, here are the pros and cons that I can think of and I am sure some equally chemically minded person will come through with many more.
MPLCs
Pros:
- Set it up and walk away (do another experiment in the time it takes to run)
- Set up a solvent gradient to allow for greater separation.
- In the case of the Industrial machines, use of software to duplicate Rf separation from TLC plates is reportedly possible.
- Ready-made cartridge columns mean you don't have to worry about packing your column.
- Loading the column requires little to no time and doesn't require you to reach high up in the hood under the sash and try load your column without disturbing the silica.
- Small scale to large scale, it doesn't matter.
- Auto collection of samples with ELSD tech to let you know where your compounds are and in which fractions.
- Reusable columns (simply flush with methanol)
- Reverse phase simply requires a different column pack.
- Column can be set to not collect until it identifies a compound.
- Can be networked and allow for notification of completion.
- Higher pressure means faster run columns.
Cons:
- Some setup time required to start the column.(Probably simply comes with time and use of the machine the user should get faster.)
- Works better with small Rf separations rather than large.
- ELSD doesn't work without a chromaphore in your compound (duh).
- TLC mimic tech doesn't always work.
- Churns through a lot of solvent (but can be optimized with Isolera "Gradient Optimization").
- Any blockage may cause detrimental effects and lots-o-mess.
- One column at a time for the basic apparatus and this can cause lab fights (grrr)
- Someone's gotta look after the bloody thing or else it'll turn to sh!t.
Pros:
- Usually able to be run fairly quickly once you are proficient.
- Can usually get a good separation especially with large Rf differences
- Close to hand and no wait time in the lab.
- Can be relaxing and give you some time to reflect on some of the finer points in your thesis.
Cons:
- Time consuming running a big column and no free hands to do other work.
- Silica is often not recycled and discarded.
- TLCing your fractions only to find it hasn't come off yet is such a biatch.
- No automatically made solvent gradients means you pretty much make up a solution of a certain polarity and run it like that.
- Loose silica is bad for your lungs (like Cancer bad)
- Loading columns can be tedious
- Packing columns can be tedious
- Exploding glass columns, rare but can happen
- Ground joints on goose necks fusing to the joint on the column, so annoying
- Tubes flying off from too much pressure