Looking for a non-endcapped C8 column

[unmgvar]

diol can be used as a HILIC phase as well, and HILIC is used to replace the NP applcations a lot more these days
this could allow yo to use friendlier solvents.
on the same note, there are several HILIC phases out there, so you need to know someting on the nature of the phase to make sure it suits you.

Sepax is interesting in the fact that they promote unlike other vendor several phases for this:
http://www.sepax-tech.com/HILIC.php

http://www.sepax-tech.com/HILIC.php

that allows also to get an idea on the other vendors possibilities
I actually used the nacalai HILIC also successfully to switch from an NP application

[Kostas Petritis]

I would actually try porous graphitic carbon columns for this one (such as Hypercarb)... you get much better resolution for "flat" compounds with minor differences in their structure.