End-capping the stationary phase is a great idea for neutral and non-polar compounds that are hydrophobic. This is common with traditional Reversed Phase stationary phases.
Polar compounds do not retain well enough on these end-capped columns but might retain and separate on non end-capped columns due to the increased polar nature of the stationary phase. However, there are better options.
While the Cogent TYPE-C™ columns do not require to be end-capped, they can retain both polar and non polar compounds in Reversed Phase or Aqueous Normal Phase ANP.
Click here to learn about TYPE-C HPLC columns