Dagne Ermias (Professor)Gashu Minbale2018-06-212023-11-092018-06-212023-11-092009-07http://etd.aau.edu.et/handle/12345678/2410Coffee is the second important raw material within the international trade, the most important foreign exchange supplier for many agricultural oriented countries, and the most popular drink. Assessment of the caffeine level is crucial to coffee quality. An HPLC-UV method with microwave assisted extraction was developed, which allowed the determination of caffeine in green, roasted, home-and coffee-house brewed coffee samples. The chromatographic separation was achieved on reversed-phase C-18 pre-packed analytical column (RP-18 Lichrospher®, Waters, 5μm, 4.6 X 150 mm i.d.) using water: Acetonitrile (70:30, v/v) as isocratic mobile phase at 0.8 mL/min flow rate. The method has been applied to samples to afford average caffeine contents (0.8-1.0%) green and roasted, (48-102 mg) home- brewed, (24-56%) coffee-house brewed. The overall procedure had percent recoveries of 93%. The within day and between day percent RSD in coffee samples ranged from 2.4-6 and 0.8-14%, respectively. HPLC-UV is a method used for caffeine routine analysis. Artemisia annua is the only commercial source of artemisinin. Due to the absence of appropriate UV absorption, artemisinin should be converted into UV active compound before HPLC analysis. It can be analyzed using Quantitative TLC method with anisaldehyde visualization reagentenCoffee and Artemisinin in Artemisia annuaThesis