Fast liquid chromatography: the domination of core-shell and very fine particles.

Columns packed with sub-2 μm totally porous and sub-3 μm core-shell particles are very widespread nowadays to conduct fast and efficient separations. In order to carry out really fast separations, short (5 cm long) columns are very popular today. The goal of this paper is to review the recent possibilities in fast or "ultra-fast" HPLC by applying short and narrow bore columns packed with modern core-shell and very fine fully porous particles. Efficiency data obtained with these recently commercialized columns from the past few years are collected, discussed and compared in terms of potential separation time and efficiency. The reasons of the success of these columns are presented. This paper also shows that theoretically expected efficiency is sometimes compromised in practical work especially in the case of narrow bore columns. The extra-column dispersion of a given LC system can also dramatically decrease the performance of small columns. It is not possible to utilize the real efficiency of these small columns in spite of their really high intrinsic separation power.