High speed HPLC particle-packed columns limitations

There is much interest in high-efficiency- and high-speed separation media for liquid chromatography. The plate numbers available in practice have been in the range of 10,000-30,000 in HPLC for 20 years or so, but these are low compared to well over 100,000 theoretical plates in capillary gas chromatography or in capillary electrophoresis. This is caused by the limitation in the use of small-sized particles for HPLC, where a particle-packed column is commonly used under a pressure-drop of up to 40 MPa. An increase in column efficiency by using small particles, which is the approach taken in the past, is accompanied by an increase in the pressure-drop, as expected from Eqns. 5.2 and 5.3, below. Eqns. 5.1-3 describe the efficiency (plate height) and flow resistance of a column packed with particles [1-3], where N stands for the... 

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