Following this, we intensified our endeavors to prevent unspecific adsorption to the column matrix. For this purpose, we (i) cut the column volume by ¾, i.e. halving the column diameter to 1 mm, and (ii) tested different quench buffers to potentially shield unspecific binding sites. At this point, we also decided to solely focus on ZrO 2 beads as TiO 2 shows (i) a lower delipidation capacity and (ii) no benefit in terms of unspecific binding on the protein level -the preferred configuration, as lipids are ideally removed predigestion to not hamper proteolysis . The smaller phospholipid trap column performs equally efficiently (~99%) in sample delipidation as demonstrated for the bigger column (Table ).