Experimental evidence of the kinetic performance achievable with columns packed with new 1.9 μm fully porous particles of narrow particle size distribution

• New sub 2 μm C18 fully porous particles with narrow particle size distribution (nPSD).
• Kinetic performance of nPSD columns is studied from an experimental viewpoint.
• nPSD columns exhibit excellent kinetic performance (300,000 N/m).
• Flat C-branch of van Deemter equation permits high-speed, high efficient separations.

Fully porous particles of narrow particle size distribution (nPSD) are now commercially available. In this paper, the kinetic performance of columns packed with these particles (1.9 μm, 80 Å pore size) has been investigated under typical reversed phase conditions by using a mixture of benzene derivatives as probes. The columns exhibited remarkably high efficiency (in the order of 300,000 theoretical plates per meter) and the possibility to be used at relatively high flow rates without loss of performance.These results contrast with previous studies on the same columns. Indeed we have found column efficiency comparable to that reported in previous work but, on the other hand, we could not observe the same dramatic loss of performance when columns were operated at high flow rates. The results presented in this paper, based on a set of six columns with different geometries (2.1 and 3.0 internal diameter × 50, 75 and 100 mm length), are not consistent with the previously proposed hypothesis that the unusually low intraparticle diffusion, which would characterize these particles, is the origin of the high efficiency of the columns. In a companion paper [1], a detailed investigation of the different terms leading to band broadening will be performed to point out the major contribution to plate height on nPSD columns.