I can recommend you publication of colleagues from my department:
DETERMINATION OF MELAMINE IN FEED BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY COUPLED MASS SPECTROMETRY
TOMASZ ŚNIEGOCKI, BARTOSZ SELL, ANDRZEJ POSYNIAK, AND JAN ŻMUDZKI
Bull Vet Inst Pulawy 54, 543-547, 2010
You can download it free:
http://bulletin.piwet.pulawy.pl/images/ ... 543548.pdf
Authors used Hypercarb column to determination of melamine in feed, but they routinely use it with other matrixes.
On the other hand I use this column for corticosteroids analysis. Proper washing is crucial. Manufacturer (Thermo) recommends long washing set with acetonitrile (overnight). Other feature of this sorbent is thermal stability - you can use high temperatures like 60-80C and higher. Such high temperatures can be also used in the washing step.