Superficially porous particles (SPP) packed in columns for liquid chromatography separations have been well demonstrated to provide superior performance capabilities for biomolecules. Our continuing refinement in design to improve SPP for separations of large biomolecules (10,000 to 1,000,000 MW) requires larger pores, with small spherical particles. Our recent studies have shown numerous advantages of SPP particles with larger pore sizes (400 Å and 1000 Å) for reversed-phase separations of large proteins and protein complexes. 1000Å pores provide optimal access to the bonded phase for very large molecules, which was otherwise unattainable. The effect is high efficiency separations of intact proteins, and larger fragments. The chromatographic advantages of narrower peaks and improved resolution for large biotherapeutics (monoclonal IgG’s and conjugates) will be demonstrated by the use of SPP particles with suitable surface chemistry compared over their fully porous counterpart. Optimal conditions that take advantage of the high performance potential of these new particles, and typical applications conditions for LC/MS analysis of larger proteins and fragments will also be discussed.