Determination of caffeine in tea by high-performance liquid chromatography and a modified digestion procedure.

A more rapid and efficient method of sample preparation was needed for caffeine determination than the ones currently available. A variation of the existing AOAC method for coffee was developed using a Tecator digestion block normally used in determining nitrogen. Replicate samples were analyzed varying the digestion time and MgO content. The analysis parameters yielding the best results were chosen for the final method.