The Dependence of Performance on Fiber Uniformity in Aligned Fiber HPLC Columns

Abstract

High-pressure liquid chromatography (HPLC) performed in columns packed with aligned fiber can require less time and pressure drop than HPLC in traditional columns packed with particles, but resolution is limited by the uniformity of the packing. A model that accounts for the band spreading caused by fibers with distributed diameters predicts that the coefficient of variation (COV) of the chromatogram of an hexagonally closest packed aligned fiber column is about 1.2 times the COV of the diameter of the fibers constituting the column packing. To test the model, HPLC columns are prepared from bundles of aligned porous silica fibers tightly packed into steel tubes. The performance of the columns is in qualitative agreement with the theory. The dependence of band spreading on nonideal packing (i.e., packing that is not all of one geometric orientation as is hexagonal closest packing) can be a reason for differences between theory and experiment.