The elution pattern of RSpak DE-413 and that of ODS column were compared. For di-carboxylic acids, the elution times of ODS column were faster than those of DE-413. To the contrary, for suberic acid whose carbon number of alkyl chain is six, the elution time of DE-413 is faster that of ODS column.


Sample : 5 μL
1. Malonic acid (n=1) 0.7 mg/mL
2. Succinic acid (n=2) 0.9 mg/mL
3. Glutaric acid (n=3) 0.9 mg/mL
4. Adipic acid (n=4) 1.2 mg/mL
5. Pimelic acid (n=5) 2.0 mg/mL
6. Suberic acid (n=6) 1.5 mg/mL

Columns      : (above); Shodex RSpak DE-413 (4.6 mm I.D. x 150 mm)
               (below); ODS column from other manfacturer
Eluent       : 20 mM H3PO4 aq./CH3CN=92/8
Flow rate    : 1.0 mL/min
Detector     : UV (210 nm)
Column temp. : 40 °C