A study of the efficiency of polybutadiene-coated zirconia as a reversed-phase chromatographic support

This work describes the dynamic characteristics of columns packed with polybutadiene (PBD)-coated zirconia. Reduced plate height (h) vs reduced velocity (v) data for alkylbenzenes were acquired for three phases coated with different amounts of PBD. Additional data for benzene (k' = 0) on uncoated and four coated phases were also collected. These h vs v plots have a minimum between 4 and 5, indicating good but not excellent column efficiency. By fitting the Knox equation to these data, the A (packing quality), B (axial diffusion), and C (mass transfer resistance) coefficients were determined. The A coefficients were about 2 in all cases, and the B coefficients had values between 2 and 3. The C coefficients varied from 0.05 to 0.2, depending on the polymer load. The data suggest that the quality of packing and the efficiency of mass transfer resistance in the "film" of polymeric stationary phase, not the stagnant mobile phase, are key to further improvements in column performance. The amount of polymer loaded significantly affects the efficiency through the mass transfer resistance in the stationary phase.