Concentration levels of essential and non-essential metals in Ethiopian khat (Catha edulis Forsk).

The levels of essential (Ca, Mg, Mn, Fe, Zn, Cr, Cu, and Co) and non-essential (Cd and Pb) metal in six different varieties of Ethiopian khat (Catha edulis Forsk, an evergreen stimulant plant) commonly consumed in the country and exported to the neighboring countries were determined by flame atomic absorption spectrometry. Known weight of oven-dried khat samples were wet-digested using 2 mL of (69-72%) HNO(3) and 2 mL of (70%) HClO(4) for 2 h and 30 min at variable temperature (120-270°C). The mineral contents in the digests were analyzed using flame atomic absorption spectrometer. The following concentrations ranges in fresh-weight basis were recorded in decreasing order: Ca (1,038-2,173 µg/g) > Mg (478.2-812.3 µg/g) > Fe (53.95-82.83 µg/g) >Zn (5.18-9.40 µg/g) >Mn (6.98-8.66 µg/g) >Cu (1.85-5.53 µg/g) > Cr (0.66-3.47 µg/g) >Co (0.41-0.80 µg/g). A wide variation in the mineral contents of khat from different region of Ethiopia was noticed. The toxic metals (Pb and Cd) were not detected in all the samples analyzed.