We all know what it is, we all know how easy it is to make a mistake, we all know how time consuming it is and we all know the dangers of dealing with fraction tubes. So the obvious question is how can you minimize manual handling?
Now, some pieces of equipment are designed to collect into larger vessels straight off the shelf. Take the Berger MultiGram II SFC, this has 4 1L bottles to collect isomers into and 2 2L bottles for the waste flow between the peaks. If you look at other off the shelf equipment, Gilson systems for example, are often sold with a 215 fraction collector which has many different rack variations. All of which contain some arrangement of fraction tubes.
However it is possible to find a cheap solution to modify a standard fraction collector into a simple two vessel system for the purification of enantiomers.
With the addition of the Gilson Valvemate II, you can run the main flow from the detector into the center position on this valve.
From this you can then setup three lines running from position 1 (Isomer 1), position 2 (waste line) and position 3 (Isomer 2) and with some clever programming setup the valve switching timings. This method also has the added benefit of collecting by time windows rather than the standard threshold method.
In summary this allows you to avoid almost 99% of the manual handling steps of combining fraction tubes, rinsing them out and avoids any cross contamination issues.
This is a modification recently employed at Reach Separations and one which is definitely helping our workflows.
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