Chromatography Forum

Hi Folks

I wanted to ask a quick educational question today. What exactly is Flash Chromatography.

I've always thought of it as preparative chromatography done with less hardware (manually deposit sample...then solvent....then let gravity pull the solvent through...etc). But now they have automated systems which inject the sample and them push it through with some type of pump. So what then really is the difference between that and preparative chromatography.

Thanks in Advance

Like so many things, not an absolute distinction, but the term "Flash Chromatography" is most commonly spplied to the use of glass columns for small-molecule separations. Originally a marketing ploy, it haas been generalized (as has "FPLC" and "Ion Chromatography").

flash means quick，a short time, it is column chromatography with some pressure.

Hello
Use vacuum and a weak solvent for sample application. And then do the step gradiet of 4-5 stages with different concentrations of acetonitrile and pH.
So it is possible to divide a lot. Dear B P Lapin said that so divided the whites almost grams for a one cicle.

The term was coined by W. C. Still in 1978 because the purification is "done in a flash" (Ref: J. Org. Chem., 1978, 43 (14), pp 2923–2925, http://pubs.acs.org/doi/abs/10.1021/jo00408a041 ).

Originally designed for silica gel, it has been expanded to other media and has become automated. For an example of automated equipment, look at http://www.isco.com ththough a quick google search will show others.

adam,

the difference today is in the costs
the columns in flash are either still hand made using glass or re-packed plastic columns or with ready made PP cartridges
the main intent is while using silica as the media since saves on costs.
today with the increase of applications you also have the possibility of using RP and other phases
but the catch are 2
1. the loadability
2. the effective separation

what we call standard columns use 60-40u particles, the better ones then go down to around 30-25u micron the more performant ones go to 20-15u
for silica you can load about 4-5% w/w on the column of sample for silica. it drops to 0.5-1.0% for RP or other medias.
in general using silica you can get very high capacity loading with very decent efficiency separations using flash instead of Prep, with a lot less cost of use.
but do not expect a 99.99% pure material. anything above 90% is good and you can with experience get close to 99%
a good real prep HPLC costs around 60-70K$, column not included.
a flash goes around 35-40K$ without columns. but the small flash columns cost 4-10$ per column.

If we go to the original question: what is flash chromatography?

I have always thought that this term is about loading the sample on the column, rinse off what ever needs to be rinsed, and then elute the compound with a step gradient. I.e. that it is more or less a desalting step that is independant on the hardware that is being used.

Or is this not a correct interpretation?

Haven't worked with flash for a while.
So in my understanding it is:
-preparative chromatography
-that uses something to 'pump' the solvent through the column (i used then 1 bar N2)
The 'pumping' is the main difference to simple open column prep chrom.
Often special columns with plugs are used.

Alex

Now，the Flash chromatography is popular technical tool in purification/preparation sample.
we could provide the Pressure 500Psi Flash system, the flow rate:100ml/min .high throughout loading.