Shim-pack Scepter C18-300 is a wide-pore organic silica hybrid reversed phase column recommended for the separation of proteins such as monoclonal antibodies and mid-sized molecules such as oligonucleic acids and peptides that may not be retained on 100-120Å pore size columns due to size-exclusion effects. Pore sizes are optimized for large molecular weight compounds and dispersed uniformly in the column, resulting in symmetrical peak shapes and increased resolution of antibodies and nucleic acids compared to a smaller pore size column.