CAFFEINE AND THEOBROMINE IN COFFEE, TEA AND COLA-BEVERAGES - SIMULTANEOUS DETERMINATION BY REVERSED-PHASE ION-INTERACTION HPLC

A new method based on reversed-phase ion-interaction HPLC is described for the identification and quantitation of theobromine, theophylline and caffeine in beverages. The interaction reagent used is octylamine orto-phosphate which also constitutes the mobile phase. The stationary phase is a microparticulate reversed-phase C-18 packing. with spectrophotometric detection at 274 nm, detection levels of 0.15, 0.30 and 0.40 ppm were achieved for theobromine, theophylline and caffeine, respectively. Quantitative analysis was performed by the standard addition method for theobromine and caffeine contents in tea, espresso-coffee, decaffeinated coffee, decaffeinated tea and cola-beverages.