NONPOROUS POLYBUTADIENE-COATED SILICAS AS STATIONARY PHASES IN REVERSED-PHASE CHROMATOGRAPHY

Non-porous silica of mean particle diameter 1.7 μm (Monospher) was coated with polybutadiene (PBD) following a published procedure. The silicas were prepared with graduated polymer loads up to 8% (w/w). Examination of the PBD-coated packings by means of electron spectroscopy for chemical analysis, scanning electron microscopy, diffuse reflection infrared fourier transform spectroscopy and differential thermal gravimetry indicated that the optimum polymer load was between 1 and 3% (w/w) with regard to a dense coverage corresponding to an average layer thickness of about 4 nm. No silanophilic interactions could be monitored using 1-3% (w/w) coated silicas under reversed-phase conditions. The small particle diameter combined with the chemically stable polymer coating allowed extremely fast and efficient separations of peptides and polypeptides under gradient elution conditions in less than 1 min. © 1990.