Apparently, the main reason was the rapid development between 19 of small, conventional, fully porous particles that provided high-efficiency columns (9). Particles of this type were commercialized by Kirkland, who prepared large, 50-µm particles in the 1970s (4,5) and 5-µm particles in the 1990s (6), with the intent to pack columns that allowed for high-efficiency separations of conventional compounds. These particles are made of a solid silica core surrounded by a shell of porous silica, a design that leads to short average diffusion paths of analytes across the particles, and, therefore, a low solid-liquid mass transfer resistance ( Cu) contribution to the van Deemter plate height equation of the column if diffusion is sluggish (8). Pellicular particles were invented and pioneered by Horváth in the late 1960s (1–3) with the specific purpose of preparing columns that could provide highly efficient high performance liquid chromatography (HPLC) separations of the constituents of high molecular weight compounds of biological origin.
We demonstrate how a detailed investigation of the band-broadening phenomena taking place in these columns has led us to challenge beliefs that are both erroneous and widespread throughout the HPLC community. This article reports on the performance of columns packed with these new pellicular particles, the kinetic mechanisms that underlie their exceptional performance in the separation of low-molecular-weight compounds, and the reasons for their current success. As a result, pellicular particles encountered little commercial success and drifted into oblivion until, in 2007, they were resuscitated as the modern sub-3-µm core–shell particles. However, pellicular particles met with stiff competition from packing materials made with high-quality, fine, fully porous particles. Pellicular particles were invented by Csaba Horváth more than 50 years ago to prepare columns providing efficient high performance liquid chromatography (HPLC) separations of high-molecular-weight compounds of biological origin.
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