I am working to analyze graphene-coated slides with MALDI-TOF , but I need to cover the surface with streptavidin and perform washing steps. I want to avoid the salts (PBS/TBS) and detergents (Tween) as they are not recommended for use with MALDI. What alternatives could I use to wash these slides and still remove unbound streptavidin/biotin.
Trenton: We had a simple strategy to mix salt-containing glycopeptide samples with matrix on the metal loading plate, let it dry and crystallize, gently wash each spot with 5-10 microliters of distilled water, let it dry again prior to collect data. Good luck.
How about using volatile salts instead, e.g., ammonium bicarbonate, ammonium acetate? To replace detergent, maybe you could use a weak volatile acid solution (however, you would need to check whether your streptavidin/biotin binding withstands it). Either way, at the end of your washing procedure I would add 1-2 washing steps with MilliQ water, just to be sure :) Good luck!
Hi Trenton
You do not give much information so I am guessing that you have coated the slide and want to remove the excess streptavidin? The best to remove the excess streptavidin would be a +- 20 mM phosphate buffer at about pH 6.5. If you do a few dips of the slide in the solution (depends on how long the slide was allowed to dry) then do a final wash by dipping into diH2O once or twice to wash away the phosphate you will be good to go.
Good luck.