Preparation of thick-film glass capillary columns by the dynamic coating procedure

Abstract

The capacity for non-polar stationary phases of the silanized inner surfaces of glass capillary columns is shown to be restricted to a 2−3×10 −7 m thick film. However, geometrical modification of a soda-glass surface by etching with HCl gas before silanization allows non-polar silicone-oil films to be prepared with average thickness (in good agreement with those predicted from the Fairbrother—Stubbs relation) as high as 14×10 −7 m. Such films are stable even after conditioning at 190°, and the column efficiencies, near 3000 theoretical plates per meter, were maintained. Van Deemter plots are similar for columns with average film thicknesses between 1 and 14×10 −7 m, thus suggesting that the surface developed through the geometrical modification is still covered with a relatively thin film of stationary phase.