You can use a small centrifugal ultrafiltration unit to reduce the volume quickly.

If you do not have access to centrifugal concentration through membranes or vacuum concentration while centrifuging you could try putting the protein solution in a dialysis membrane and hanging it in an airflow and the water will evaporate leaving a more concentrated solution. If speed is important and you do not mind some loss of protein you can swell a tiny amount of sephadex ( of a grade that excludes your protein) and the supenatant will be at a higher concentration

A quick method would be using concentrator columns. Very rapid and easy to use.

Thank you,

Amal.

Dear Kimimuepigha Ebisine

i'm agree with Adam

ultrafiltration concentrators (as amicon ultra 0,5ml) as the fast and simple solution. In few minutes you can reduce the sample volume and recover the sample with out affect the buffer composition.

At the following link you can find the 10KDa cutoff

https://www.sigmaaldrich.com/IT/en/product/mm/ufc5010

but you can choose different cutt-offs (eg. 3-10-50KDa) on the basis of the MW of the protein that you would like to concentrate.

HOwever there are no problem if you would like to use small cutt off to concentrate big proteins, it will just require more time...

eg to concentrate from 500ul to 100ul with a 50KDa you can need 2-5 minutes on the basis of your protein buffer and concentration, using a 3KDa is possibile that you need 10-20 minutes.

good luck

Manuele