Placing a spin column in a 15 ml tube, after stirring the purification resin,1.5 ml of the suspension was added into the column and allowed to settle by gravity. The spin column was placed in the provided collection tubes and centrifuge for 3 minutes at 4000 rpm. 100 µL of the antibody bound to the Alexa was added to the center of the spin column, allowing the solution to absorb into the resin bed. the spin column was placed in an empty collection tube and centrifuged for 5 minutes at 4000 rpm. A small amount of the purified conjugate was diluted using 2ml FPBS.