Comparison of metal content of coffee samples grown in different countries by icp-oes

Coffee is the one of the most consumed beverage across the world. Therefore, it has enormous commercial value and social importance. Coffee consumption continues to increase due to its physiological effects, its pleasant taste, aroma and many health benefits. Robusta and Arabica are two basic types of coffee beans. Turkish coffee is a method of preparation, not a kind of coffee bean grown in Turkey. The coffee beans used for Turkish coffee is generally Arabica type coffee beans. This study was aimed to determine the concentrations of some major, minor and trace elements in six different coffee samples from six different origins (Brazil, Colombia, Ethiopia, Guatemala, Kenya, and Yemen) where the coffee plants grown. The coffee samples were analyzed for seventeen elements (Al, As, Ba, Ca, Cr, Cu, Fe, K, Mn, Na, Ni, P, Se, Sn, Sr, Zn, and Mg) by using inductively coupled plasma optical emission spectroscopy (ICP-OES). Prior to the analysis by ICP-OES, all coffee samples were completely digested in aqua regia. According to the obtained results, the determined elements were classified into three groups (macro, micro, and trace) elements according to their concentration in different coffee samples; among the macro elements potassium (K) showed the highest levels in all coffee samples whereas the concentration of calcium (Ca) were found to be lowest in the group of macro elements. Micro elements showed the concentration order of: Sr > Mn > Fe > Al > Ba > Cu > Zn in all coffee samples. Concentrations of nickel (Ni) were higher than all other elements in the group of trace elements. The results obtained in present study showed good agreement with previously reported studies for most of the elements especially micro and trace elements while the results for macro elements were generally lower than reported values. Statistical analysis of the results showed significant differences in the concentration of each element in different coffee samples of different origins.