Determination of Caffeine in Some Sudanese Beverages by High Performance Liquid Chromatography

Abstract

Simple High Performance Liquid Chromatographic (HPLC) method was validated for determination of the content levels caffeine in 15 different beverage samples commercially available in Sudan local markets. Shim-pack VP-ODS column was used with methanol: water (30:70)% (v/v) eluent. The detector wavelength was set at 270 nm. Linearity of the method was check from 10-100 ppm and the correlation coefficient was 0.9999. The method detection limit was 0.023 ppm and the precision was 1.25% at 40 ppm caffeine concentration.. the spiked recoveries for caffeine were 99%, 105%, 99.2%, 102% and 102% in Pepsi Cola, Coca Cola, Red Bull, Gazaltain black tea and Coffee samples respectively. The caffeine contents in tea samples ranged from 440 ppm to 473 ppm with average concentration of 458.6 ppm. The caffeine concentrations in energy drinks samples ranged from 170.6 ppm to 324 ppm with average concentration of 255.6 ppm. The coffee sample contains 252.4 ppm. The carbonated soft drinks showed caffeine content in the range of 32.4 ppm to 133.3 ppm with average concentration of 96 ppm. In addition, the concentrations of caffeine have been converted into the daily intake doses based on beverages consumption. The mean values of caffeine daily intakes were 183 mg, 101 mg, 64 mg and 38 mg through the ingestion of tea, coffee, energy drinks and soft drinks, respectively.