Packing procedure of silica columns for HPLC with aqueous slurries

Abstract

SummarySuccessful packing of high quality HPLC columns is dependent upon a number of parameters. Especially when using slurry packing techniques, the absence of conglomerates of particles in the slurry and the wettability of the particles are important. The method described in this paper fulfills these conditions, imparting a t; potential to the 5 and 10 pm silica particles by applying a pH gradient. This results in repulsive forces between the particles and hence leads toa well-controlled monodisperse situation. Water is used as a slurry and displacement liquid; it combines the advantages of excellent wetting properties and non-toxicity.

Optimization of the packing process of microcolumns with the embedded phosphodiester stationary phases

“…The zeta potential results for slurries of stationary phases (A) Diol-P-C10, (B) Diol-P-C18, (C) Diol-P-benzyl, and (D) Diol-P-chol. Some results were not obtained, mainly for hexane (3) and water (10) due to the high instability of the suspensions making it difficult to obtain a result. The solvents used are listed in the table beside F I G U R E 4 Optical microscope images for stationary phase slurries of Diol-P-C10 in methanol (A), isopropanol (B), and acetonitrile (C).…”

“…Initially, a concentration of 1–30% (w/w) was recommended, and a concentration of 10% was optimal for packing at pressures of 400–500 bar. Nevertheless, using too high pressure with modern stationary phases can lead to the formation of fine particles from the broken stationary phase beads [9, 10]. The last and crucial step in packing is the exchange of solvents in the column and conditioning under the conditions in which it will operate [8].…”