pseudo reversed phase versus hilic

[olivia]

Hi, can anyone tell me, if psuedo reverse phase chromatography is the same as hilic and if so, what is the minimum amount of organic that can be used.
Hope someone can help
Thanks
Liv

[tom jupille]

Considering the fact that I've never heard the term "pseudo reversed phase" before, and that a Google search turns up only two references (your post being one of them), I rather suspect that it does refer to what many people refer to as "HILIC" (and to what used to be called "normal phase" for carbohydrate separations on amino bonded phase columns).

If you think about the definitions of "reversed-phase" (mobile phase more polar than stationary phase; retention increases with increasing mobile phase polarity) and "normal phase" (mobile phase less polar than stationary phase; retention decreases within increasing mobile phase polarity), you realize that it's a moving target. A number of columns show reversed-phase behavior at low organic % and normal-phase behavior a high organic %, with a transition region of more or less constant retention in between. The percentage organic involved depends on the chemistry of the stationary phase and on the analyte.