When 10 mM ammonium acetate buffer was used as an eluent, each column showed a good chromatogram. When the ammonium acetate concentration was lowered to 1 mM, both ODS columns showed tailing peaks caused by interaction between scopolamine and the residual silanol groups in the column.
On the other hand, polymer based ODP2 HP-4D showed no non-specific adsorption of scopolamine to the media even when the ammonium acetate concentration was lowered. Scopolamine elutes with a sharp peak. As elution time and peak shapes are not affected even if the salt concentration in the eluent is lowered, ODP2 HP columns are suitable for ESI methods (LC/MS) where salt concentration in the eluent affects ion suppression of the sample.


Sample : 5 μL
Scopolamine (pKa7.6) 300mg/L

Columns      : Shodex ODP2 HP-4D (4.6 mm I.D. x 150 mm each) 
               ODS(A), ODS(B) from other manufacturer (4.6 mm I.D. x 150mm each)
Eluent       : Ammonium acetate buffer (pH7.0)/CH3CN=35/65
Flow rate    : 1.0 mL/min
Detector     : UV (254 nm)
Column temp. : 40 °C