FAQ: How can I determine if my target protein remains bound to the resin?

Add 200 µl of SDS-PAGE loading buffer to the column, pipette up and down and remove an aliquot of the resin from the spin column.  Incubate at 70°C for 5 minutes to release any protein that remains on the resin following elution. Load and analyze proteins by SDS-PAGE. Most proteins, regardless of whether they bind to the nickel or to the agarose-bead itself, will be recovered by this procedure.