To exclude the influence of the nature of the analyte on “Cs”term effects, ferulic acid was also analyzed in the NP
as it is able Fig to undergo similar strong interactions as in the HILIC mode. When comparing the van Deemter
plots for ferulic acid in the HILIC mode (Fig. 2B) and the NP mode, a significant improvement in the HETP at
high flow rates can be seen for the SPP column tested in NP mode.