Sigma Aldrich Ascentis Express HPLC columns

Ascentis Express HPLC columns, through the use of Fused-Core particle technology, provide both high speed and high efficiencies of sub-2 µm particles while maintaining lower backpressures. The combination of high efficiency and low backpressure benefits UPLC (or other ultrahigh-pressure system) users as well as conventional HPLC users.

The increased efficiency of Ascentis Express columns equates to the use of shorter columns and lower volume of solvents.

Ascentis Express Fused-Core 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 Ascentis stationary phases have been evaluated for MS compatibility during their development and the Express phases are no exception.

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.