Determination of caffeine content of tea and instant coffee brands found in the Kenyan market.

Abstract

Caffeine (1, 3, 5-trimethylxanthine), a mild addicting drug though used for medicinal purposes is the active ingredient that makes tea and coffee valuable to humans. In this study, the levels of caffeine in certain coffee (nescafe, africafe, dormans) and tea (chai mara moja, kericho gold, sasini, finlays premium) brands found in the Kenyan market were determined using high performance liquid chromatography (hplc) and UV/ Vis spectrophotometric methods. The levels of caffeine in all the tea and coffee brands were found to be within the documented range. The order of caffeine concentration in tea samples was found as follows: chai mara moja > finlays premium > kericho gold > sasini. In coffee it was found that the caffeine content of africafe > nescafe > dormans. Generally, higher concentration of caffeine in all the samples were realized with the UV/ Vis spectrophotometric method compared to hplc method indicating that acidified water was a better caffeine extractor than pure water.       Key words: Caffeine, tea, coffee, high performance liquid chromatography, UV/ Vis spectrophotometry, SPE chromatography.