Theobromine, theophylline, caffeine were separated by RSpak DE-413 (4.6 mm I.D. x 150 mm) and DE-213 (2.0 mm I.D. x 150 mm). As DE-213 is a semi-micro type column, it can be also used for LC/MS.


Sample :
1. Theobromine
2. Theophylline
3. Caffeine

(Left)                             
Column       : Shodex RSpak DE-413 (4.6 mm I.D. x 150 mm)
Eluent       : H2O/CH3CN=75/25                      
Flow rate    : 0.5 mL/min
Detector     : UV (254 nm)
Column temp. : 30 °C
(Right)
Column       : Shodex RSpak DE-213 (2.0 mm I.D. x 150 mm)
Eluent       : H2O/CH3CN=75/25
Flow rate    : 0.1 mL/min
Detector     : UV (254 nm)
Column temp. : 30 °C