We investigated the robustness of the entire delipidation system by recurring POPC injections (30 injections) with appropriate cleaning (3% NH 4 OH in methanol) of the phospholipid trap column, both ZrO 2 and TiO 2 , in between. Advantageously, the column regeneration occurs simultaneously to the analytical gradient. The subsequent wash run -a step commonly applied to prevent sample carry-overwas applied to not only clean the C4 trap column but also to re-equilibrate the phospholipid trap column to solvent A (0.23% formic acid), i.e. to pH 2.5. The delipidation efficiency is comparable with previous results (Table ) and, most impressively, remains over 99% for ZrO 2 throughout (Figure ). The delipidation rates obtained for TiO 2 are slightly lower (~97-98%), yet reasonably sufficient, and show a drop by 3% within the last three injections.