Determination of chromatographic the amount of the caffeine in coffee according to the preparation method

Today, coffee is a functional foodstuff because of its antioxidant and beneficial biological properties. Caffeine, coffee beans (Coffea arabica and Coffea robusta) and tea leaves (Camellia siniensis), which are among the world's main sources, as well as cola nuts (Cola acuminate), coca beans (Theobroma cacao), yerba mate (Ilex paraguariensis) and guarana berries (Palexin) cupana) is a purine alkaloids of the methylxanthine family. It is a substance found naturally in the leaves, seeds or fruits of 63 plant species worldwide. For adults, the caffeine dose should be <400 mg/day. When taken in large amounts, withdrawal symptoms such as irritability, insomnia, tremor and anxiety are observed. The positive side of caffeine intake is that it helps prevent various diseases such as type 2 diabetes, Parkinson's and Alzheimer. It also has antioxidant and anti-cancer activities. Within the scope of this thesis, the change of caffeine amount in coffee according to brewing methods was determined by YPSK-DAD method. Caffeine analysis was performed with 10 μL injection volume, 274 nm wavelength, flow rate of 0,7 mL / min, 45% (v/v) Methanol: water mobile phase, PFPP (Pentafluorophenyl propyl) (200mm x 4.6mm x 5μm) column. The column temperature was maintained at room conditions. Since the experiment with DAD detector has simple and fast process steps, the correlation coefficient is calculated as 0.9998, the detection limit is 0.088 ppm and the determination limit is 0.029 ppm from the calibration graph in the concentration range of 10-50 ppm. %96.81- 101.03 results were obtained in recovery studies.