Remove C4 Ziptip from p20 pipette and place safely back into tip box to hold. Take a p200 pipette set at 200 µL and add a p200 pipette tip to the end. Take the p200 with pipette tip and then add the C4 ZipTip to the end. Carefully pipette the elution sample up and down for a total of 10 times per elution fraction. Avoid forcing air bubbles through the pipette tip as this will disrupt the resin and introduce oxidation to the target protein.