The Study of Adsorption Effects on Taylor Dispersion Analysis of Proteins

In the present work, we investigated protein adsorption in fused silica capillaries under typical Taylor dispersion analysis (TDA) conditions, including standard sample volumes, concentrations, flow parameters, and capillary dimensions. To reduce protein adsorption, the bare fused silica surface-containing deprotonated SiOH groups-was briefly washed with the analyte protein to form a dynamic but quite stable precoating. The subsequently injected protein peaks exhibited good reproducibility. The advantage of the present method is that the background signal does not interfere with the analytical response of the sample, resulting in improved detection sensitivity. Furthermore, for certain detectors (e.g., MS), the continuous introduction of a protein solution-even at low concentration-can be avoided. Although peak tailing did not disappear completely, the peak asymmetry measured at 50% peak height was better than 0.9 for neutral and acidic proteins. To minimize the effects on the results caused by adsorption-induced peak broadening in the resulting taylorgrams, the peak width (peak variance) used for diffusion coefficient determination was taken as twice the front half-width at 50% peak height.