Jul 19 2007
Scientists from Supelco, a member of the Sigma-Aldrich group, have effectively extended the use of high-resolution liquid chromatography (LC) by exceeding 120,000 plates/column under moderate operating conditions using commercial instrumentation. The enabling technology is the Fused-Core(TM) particle inside the Ascentis Express HPLC Columns.
Ascentis Express columns provide a breakthrough in high-resolution LC performance. Based on Fused-Core particle technology, Ascentis Express provides the high efficiency based benefits of sub-2 micrometer particles but at a much lower backpressure. Due to the high efficiencies at low backpressures, Ascentis Express can provide high-resolution chromatography that was previously unattainable on commercial LC systems.
"With instruments capable of operating up to 15,000 PSI, a quarter million plates per column may be possible," said Wayne K. Way, Market Segment Manager HPLC at Supelco.
The Fused-Core particle consists of a 1.7-micrometer solid core and a 0.5-micrometer porous shell. A major benefit of the Fused-Core particle is the small diffusion path (0.5 micrometer) compared to conventional fully porous particles. The shorter diffusion path reduces axial dispersion of solutes and minimizes peak broadening. In fact, Ascentis Express columns are able to achieve efficiencies of 240,000 N/m, which is similar to that obtained with sub-2 micrometer particle columns, even though the backpressures are only 50% of that achieved under similar conditions with sub-2 micrometer particles. This means that Ascentis Express can turn almost any LC system into a high-resolution workhorse for a research lab.
In the study to be released at HPLC 2007, an international symposium on high performance liquid phase separations and related technologies held June 17-21 in Belgium, four Ascentis Express columns were coupled together to create a 55 cm X 4.6 mm column. Using moderate operating conditions of 1 mL/min flow rate, 50C column temperature, and an isocratic mobile phase composition of acetonitrile/water, efficiencies of greater than 100,000 were measured on all peaks in a test mix of five compounds. Benzene and deuterobenzene were baseline resolved and the column backpressure was just 7,000 PSI as measured on the Agilent 1200 LC system.