Determination of trace metals in commercially available Khat (Catha edulis Forsk) in Addis Ababa Graduate Project
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Date
2009-06
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Addis Ababa Universty
Abstract
Khat (Catha edulis Forsk) is a plant that grows in certain areas of East Africa and the Arab
Peninsula. A large number of people in Ethiopia chew khat leaves because of its pleasurable and
stimulating effects. In the present study the level of selected Trace metals ( Cu, Zn, Mn, Ni, Co,
Cr, Cd and Pb) in four different kinds of khat sampled from different khat shops in Adiss Abeba
were analyzed. Known weights of oven dried Khat samples were digested by wet digestion using
3 mL of HNO3 ,1 mL of HCLO4 and 1 mL of H2O2 by setting the temperature first to 60 0C for 30
min and then increased to 210 0C for the next 2 h and 30 min. The contents of the minerals in the
digests were analysed using flame atomic absorption spectrometry. The following concentration
ranges in dry weight (μg/g) were obtained in the khat samples: Cu (19.2 - 24.4); Zn (24.1 – 46.9);
Mn (14.92 – 20.6); Ni (4.7 – 7.7); Co (3.1 – 7.76); Cr (3.1 – 6.76); Cd (1.3 – 2.9) and Pb (4.8 –
9.1). Among the essential metal analyted Zn was the most abundant one followed by Cu,Mn,and
Ni Whereas Co and Cr were less than Pb. Generally ‘Bahirdar’ Khat contained higher
concentration compared to Gelemso, Gurage and Wondo for the majority of the mineral nutrients
identified. The tested four kinds of khat proved high variability (p<0.05) in their content of trace
metals. The possible uptake by the human body from fresh khat has also been determined. Except
Cd and Pb the amount of metal that one may take through consumption of fresh khat alone were
found to be below the recommended daily allowance
.
Key Wordes: Khat (Catha edulis Forsk), Bahirdar, Gelemso, Gurage, Wondo,
Adiss Abeba, Trace metal, Flame Atomic Absorption Spectrometry
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Keywords
Khat (Catha edulis Forsk); Bahirdar; Gelemso; Gurage; Wondo; Adiss Abeba; Trace metal; Flame Atomic Absorption Spectrometry