Solid-Core or Fully Porous Columns in Ultra High-Performance Liquid Chromatography—Which Way to Go for Better Efficiency of the Separation?

The emergence of ultra high performance liquid chromatography UPLC? system at 2004, which operated narrow bore columns with sub-2m particles, marked also the re-introduction of solid core type of particles in the format of sub-3 m, as a self claimed alternative route to improve chromatographic efficiency. The reasoning was based on the theoretical predictions of reduced band broadening due to the reduced path of the molecules inside the stationary phase as a result of the solid core. Nevertheless, soon enough it was observed, as shown in many publications, that these columns should better be operated in ultra-high performance liquid chromatographic systems to get efficiency closer to their expected theoretically values to fulfill their potential.

Theoretical works discussing efficiency of the chromatographic separation by using Van Deemter, Knox and Giddings theories were brought here in an effort to explain this extra efficiency of solid core columns. These works were actually aiming also to revisit some of the wrong widespread notions behind some explanations in the literature attempting to clarify the origins of this improved efficiency.