Response to “Comments on ‘Hydrodynamic and dispersion behavior in a non-porous silica monolith through fluid dynamic study of a computational mimic reconstructed from sub-micro-tomographic scans”’

• We respond to comments made by Hlushkou et al. (2013) [1] (JCA-13-207).
• Rationale behind identifying scanning resolution explained.
• Steady-state velocity field simulated to explain axial velocity distribution.
• Diffusion and axial dispersion simulations repeated to explain anomalies.

We respond to the comments made by Hlushkou et al. (2013) [1] (JCA-13-207) to our earlier work [J. Chromatogr. A 1274 (2013) 65], wherein the authors have questioned the validity of our reconstruction of the bulk macropore space in a silica monolith and challenged the interpretations from subsequent computational fluid dynamic simulations. We provide an explanation as to why a monotonic trend in external porosity values cannot be expected with decreasing scanning resolutions. The observed deviations of the pore and skeleton size distributions from those in literature are explained based on the differences in methods used to calculate these distributions. The difference in the scaled axial velocity frequency distributions is explained based on the assumptions made and the distributions are redrawn to reflect the said assumptions. The normalized transient diffusion (peak parking) and dispersion simulations are repeated with a higher resolution of detection planes to measure the variance of spreading pulse, thereby providing an explanation for the anomalies pointed out in our earlier work. Finally, we explain our comparison of the computational expenses with previous work as a study of the trade-off in accuracy that results from the lower resolution scan and use of commercial CFD packages.