Why does a column with smaller particles produce higher efficiency than a column packed with bigger particles even they have the same pore size and surface area?
Pore size (in fact pore diameter) and surface area have nothing to do with pore length. Since typical silica gel has a uniform porous structure (not just pores on the surface region) the pore’s length is in direct proportion to the size of the particles. The UPLC is one example of an attempt to improve column efficiency by going to extra short pores (i.e. extra small particles).
