HPLC Columns for Biotechnology 

ZORBAX 300Extend-C18 is a wide-bore HPLC column for high efficiency separations of peptides, polypeptides, and small proteins from pH 2 - 11.5. Extend-C18 and 300Extend-C18 columns incorporate a unique patented bidentate silane, combined with a double-endcapping process that protects the silica from dissolution at high pH . At high pH, the retention and selectivity of peptides can change dramatically as a result of changes in amino acid charge. Excellent recoveries of hydrophobic polypeptides have been achieved at high pH. In addition, LC/MS sensitivity of peptides can also be improved at high pH using a simple ammonium hydroxide mobile phase. These conditions allow for ions to be detected in both positive and negative ion modes simultaneously. Columns are best applied for separations of compounds that are either (1) basic and have little or no retention at low or intermediate pHs, (2) more stable or more soluble at high pH, or (3) basic and show poor peak shape at low or intermediate pH.