QUANTIFICATION OF CAFFEINE IN BEVERAGES USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A method based on reversed-phase (C18) HPLC was used for identification and quantitation of caffeine. Methanol: water (40:60, v/v), as a mobile phase at 0.7mL/min and absorbance detection at 273nm was used, The detection limit (S/N=3) was 1ng/mL and the precision for ten different injections was under 3.2%, Caffeine levels found in brazilian cola-beverages (2 - 41mg/can), tea (2 - 40mg/150 mL) and coffee (0.2 - 109mg/150 mL) were lower than the reported in the literature for the corresponding products available in the U,S,A or Europe. The method proposed here is suitable for quantitation of caffeine in beverages with the advantages of the fact that no pretreatment or derivatization of the samples is required. In addition, it can also be used as an HPLC experiment in courses related to chromatography or food control.