Ascentis Express HPLC columns

Ascentis Express HPLC columns, through the use of fused-core particle technology, provide both the high speed and high efficiencies of sub-2 μm particles while maintaining lower backpressures. This combination benefits UPLC (or other ultra high pressure system) users as well as conventional HPLC users, with the increased efficiency of the columns equating to the use of shorter columns and lower volume of solvents.

The particles were designed with LC-MS in mind. Even extremely short column lengths exhibit sufficient plate counts to show high resolving power. The flat van Deemter plots permit resolution to be maintained at very high flow rates to maximise sample throughput.

All stationary phases have been evaluated for MS compatibility during their development. The pentafluorophenylpropyl stationary phase of Ascentis Express F5 provides a stable reversed phase packing with electron-deficient phenyl rings due to the presence of electronegative fluorines. In addition to forming p-p and mildly steric interactions, F5 phases also retain compounds by polar interactions.

As a result of having both polar and non-polar character, F5 phases can show dual-mode retention behaviour, sometimes producing a ‘U-shaped’ retention as a function of acetonitrile content of the mobile phase, with retention increasing at both low and high concentrations of ACN (reversed-phase and HILIC retention modes). Ascentis Express F5 can be used for basic, acidic or neutral compounds with alternate selectivity from C18.

Currently, C18, C8, RP-Amide, and HILIC (bare silica) phases are available for Ascentis Express.