The relation between the percent organic solvent (acetonitrile) in the eluent and the theoretical plate number (TPN) and the relation between the organic solvent concentration and retention time for ODP2 HP 4D (4.6 mm I.D. x 150 mm length) are shown. For each sample the highest efficiency occurs when the content of organic solvent is 40 to 45 %. The retention time of each sample rapidly increased when the content of acetonitrile was 40 % or below. A mobile phase of 45 % acetonitrile is recommended as a starting point for general analysis.


Sample : 5 μL
Phenol 300 μg/mL
Methyl bezoate 350 μg/mL
Toluene 1000 μg/mL
Ratio of TPN [%] : TPN at acetonitrile 40 % is set as 100%.

Column       : Shodex ODP2 HP-4D (4.6 mm I.D. x 150 mm)
Eluent       : H2O/CH3CN
Flow rate    : 0.5 mL/min
Detector     : UV (254 nm)
Column temp. : 40 °C