Multi-element determination of essential and toxic metals in green and roasted coffee beans: A comparative study among different origins using ICP-MS

Abstract

The aim of this study is to compare the elemental composition among different coffee varieties consumed in Jordan. Levels of different metallic elements in coffee samples; green and roasted coffee beans from five origins; Brazil, Ethiopia, Kenya, Columbia, and India, collected from the Jordanian market were investigated. Twenty-two elements, including essential and toxic elements such as potassium (K), magnesium (Mg), calcium (Ca), iron (Fe), aluminum (Al), manganese (Mn), copper (Cu), barium (Ba), strontium (Sr), zinc (Zn), chromium (Cr), lead (Pb), nickel (Ni), vanadium (V), cobalt (Co), gallium (Ga), uranium (U), cadmium (Cd), silver (Ag), lithium (Li), indium (In), bismuth (Bi), thorium (Th), and thallium (Ti), were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The detected heavy metals and their intake per 1 cup of coffee did not largely contribute to the recommended daily intake (RDI) and tolerable upper limit of daily intake (TULD) in an adult with an average body weight of 80 kg. The ICP-MS versus flame atomic absorption spectrometry (FAAS) results were linearly fitted, and the correlation coefficients ( R2 > 0.95) were better than 0.95 for the three checked elements. No significant difference between the results of the two techniques was observed ( p > 0.05). The ANOVA results indicated the presence of a significant difference between the levels of Cr, Co, and Zn in green and roasted coffee beans. The results of this study indicated that the coffee consumed in Jordan did not contain toxic levels of heavy elements and is safe for consumption according to health organizations.