The relations between the theoretical plate number (TPN) and flow rate and also between retention time and flow rate were investigated using ODP2 HP 4D (4.6 mm I.D. x 150 mm length). Each sample showed the highest TPN at the flow rate of 0.4mL/min, while efficiency decreased at 0.3 mL/min and below due to sample diffusion. Also, each sample showed extremely long retention times at 0.5mL/min and below. Therefore a flow rate of 0.5 - 1.0 mL/min is recommended for general analysis using ODP2 HP-4D. Flow rate of 0.1 - 0.2 mL/min are recommended for ODP2 HP-2D (2 mm I.D. x 150mm length).


Sample : 5 μL
Phenol 300 ppm
Methyl bezoate 350 ppm
Toluene 1000 ppm
* Ratio of TPN [%] : TPN at a flow rate of 0.5 mL/min is set as 100%.

Column       : Shodex ODP2 HP-4D (4.6 mm I.D. x 150 mm)
Eluent       : H2O/CH3CN=55/45
Detector     : UV (254 nm)
Column temp. : 40 °C