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 microm Kinetex-C(18) shell particles was investigated in gradient elution chromatography and compared with those of the 2.7 microm Halo-C(18) shell particles and the 1.7 microm BEH-C(18) totally porous particles. The peak capacities P(c) 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 A versus 130 A), the column packed with 2.6 microm shell Kinetex-C(18) particles gives an equivalent or even slightly better separation of biomolecules having a size and a mass around 40 A and 15 kDa, respectively, than the column packed with 1.7 microm BEH-C(18) 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.