Abstract
Coffee is the most popular beverage after water and is consumed worldwide. Its consumption in high amount may pose health risks. Moreover, most of the market's available coffee beans products do not mention their proper amount of caffeine. To develop an efficient and reliable method of caffeine extraction in commercial coffee brands, automated solvent extraction was used along with a sensitive, rapid and precise method for simultaneous analysis of caffeine using ultra-high performance liquid chromatography coupled with an ID-X-Orbitrap Mass spectrometer (UHPLC-IDX-Orbitrap-MS). The results showed comparable values to previously published studies. The lowest average amount of caffeine (mu g/g) was in the Colombian brand (6.7) and Brazil-CF brand (7.1). The highest average amount of caffeine (mu g/g) was in Brazil-C brand (10) and Kenyan brand (10.4). For the rest of coffee beans extract, the caffeine amount was similar varying between 7.7 and 9.7 mu g/g. The results demonstrated that the proposed procedure is highly reproducible (with an RSD error of less than 20% for most of the analytes) and the recovery levels of the target compound (i.e., caffeine) varied in the range of 45-88%. Moreover, the limit of detection of caffeine was equal to 1 ng mL(-1). This was a pilot study to examine caffeine extraction from different coffee sources and a future study will identify all active compounds.