Organo-silica nano-particles used in ultrahigh-pressure liquid chromatography

A simple one-step process was used to synthesize uniform, spherical organosilica nano-particles containing octadecyl moieties. These nano-particles, having a diameter of 670 nm, were slurry packed into fused-silica capillary tubes of 50 μm internal diameter and tested for use in ultrahigh-pressure liquid chromatography (UHPLC) at inlet pressures of about 50,000 psi ( ∼ 3,500 bar), providing for the use of HPLC with nano-particle packed columns. The retention characteristics of a column packed with the organo-nano-particles were shown to be stable under acidic (pH < 1) and basic (pH > 11) conditions. Fast analysis times and relatively high separation efficiencies ( ∼ 500,000 plates m^-1) were obtained under the conditions used.