Simultaneous determination of heavy metals in Tahini by anodic stripping voltammetry

Document Type : Original


1 Department of Drug and Food Control, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.

2 Halal Research Center, Ministry of Health and Medical Education, Tehran, Iran.


Background and objective: Tahini is a regional dish prepared from sesame seeds and consumed as breakfast worldwide. It is a good source of zinc, copper, and group B vitamins. However, the product may be contaminated with toxic heavy metals. Therefore, our purpose was development of analytic method for simultaneous determination of zinc, copper, lead, and cadmium in Tahini.
Materials and methods: Our work was conducted on 37 brands of Tahini (n = 74). The samples were purchased from local market of Tehran (Iran). Concentration of heavy metals was measured by polarograph. Voltammetric analysis was carried out by using 746 VA trace analyzer by differential pulse anodic stripping Voltammeter at Hanging mercury dropping electrode.
Results and conclusion: Concentration of Zn, Cd, Pb, and Cu was calculated as 3.79 ±2.43, 1.48 ±0.08, 0.015 ±0.01, and 0.012 ±0.007 µg/100 g, respectively. Amount of Pb and Cd was lower than acceptable limit approved by CODEX in all the samples, while concentration of Cu and Zn was within the standard range. According to our investigation, Tahini can be used as a valuable food to meet the nutritional needs without any toxic effect arisen from deleterious heavy metals in the consumers.


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