Dichloromethane (Aldrich, Germany), chloroform (Riedel–Detlaen) distilled and de-ionized water (AAU, Ethiopia) were used. A caffeine sample was obtained from Evan, England and Arabic coffee beans were provided by Ethiopia coffee and tea quality and liquoring center, Ethiopia, which were washed at the export standard of the center. The coffee samples were collected from the southern part of Ethiopia regions (the specific areas are Benchi maji, Gediyo yirgachefe, Tepi, Godere Goma limu, and Besema) without considering their varieties.