can I use 1.5 m buffer as mobile phase

[avikparekh]

Hi
Can I use 1.5 molar potassium dihydrogen phosphate . pH 3. On a beta cyclodextrin column.my compound is epinephrine

[Andy Alpert]

Cyclodextrin coatings have their hydroxyl- groups facing outwards. This makes the exterior hydrophilic and the core hydrophobic. Retention as a function of % organic solvent follows a U-shaped curve, with retention at low % organic due to hydrophobic interaction with the core and retention at high % organic due to hydrophilic interaction with the exterior. In your case, I speculate that using that much phosphate salt will cause epinephrine to be retained by hydrophobic interaction with the core. Is that what you want?

[M_Farooq]

Never run purely aqueous concentrated buffers through the sugar based columns. There are much better ways of retaining compounds on such columns as Andy has mentioned. If it is absolutely necessary you can attach a small bare silica guard column before the injector. Now the eluent will be less damaging to the stationary phase because of saturation with dissolved silica. Have you tried "polar organic mode" in which polar compounds can be retained or even HILIC mode (high ACN and low buffer)?