Performance of columns packed with the new shell Kinetex-C18 particles in gradient elution chromatography

The performance Of columns packed with the new 2.6 mu m Kinetex-C-18 shell particles was investigated in gradient elution chromatography and compared with those of the 2.7 mu m Halo-C-18 shell particles and the 1.7 mu m BEH-C-18 totally porous particles. The peak capacities P, of these columns were derived from the resolution of the components of a peptide mixture (beta-Lactoglobulin digest) and of a mixture of two biomolecules (insulin and lyzozyme). The three columns exhibit the same peak capacities for the peptides at low linear velocity (u(0) < 0.05 cm/s) and at any gradient steepness (0.8 < G < 10). When the linear velocity is increased 10-fold. the peak capacity of the Kinetex column remains nearly unchanged while those of the Halo-C-18 and the BEH-C-18 columns decrease by 20%, approximately. This result confirms the very flat HETP curve, the very low C term of the Kinetex column and its ability to successfully operate at high flow rates while experiencing less efficiency loss than other columns. Despite its smaller average mesopore size (96 angstrom versus 130 angstrom), the column packed with 2.6 mu m shell Kinetex-C-18 particles gives an equivalent or even slightly better separation of biomolecules having a size and a mass around 40 angstrom and 15 kDa, respectively, than the column packed with 1.7 mu m BEH-C18 totally porous particles. This result demonstrates the advantages of the shell versus the conventional particle technology when it comes to resolve mixtures of large and slow diffusive biomolecules. (C) 2010 Elsevier B.V. All rights reserved.