According to the van Deemter equation, which describes the relationship between linear velocity (flow rate) and plate height (HETP or column efficiency), when the particle size decreases to <2.5 μm not only is there a significant gain in efficiency, but the efficiency does not diminish at increased flow rates or linear velocities.

In order to accurately and reproducibly integrate an analyte peak, the MS must have a sufficient acquisition rate to capture enough data points across the peak (>10 points/peak), requiring very short dwell times and interchannel delays on a triple quadrupole instrument or the fast spectral acquisition of the TOF analyzer and the software tools to handle the increased number of results.

p77, Analysis of Pesticides in Food and Environmental Samples, CRC Press, 2008, edited by José L. Tadeo