Preform fabrication conditions for pure fused silica capillary fiber using MCVD.

We report specific conditions for preparing pure fused silica capillary fiber by the method of Modified Chemical Vapor Deposition (MCVD). Fused Silica capillaries are used in capillary column chromatography. Using the fabrication conditions discussed, capillary fiber of 250microns x 350microns has been drawn from preforms that have pure silica deposited on the inner surface by MCVD. Through intermediate surface testing, the inner surface of the fiber shows to be less acidic, less adsorptive of organic compounds, and more reproducible from batch to batch then fiber made from commercially available fused silica. These are significant properties needed for capillary column chromatography.