Determination of metals in pepper by flame atomic absorption spectroscopy

Abstract

The health risk of dietary intake of metals by humans cannot be over-emphasized, especially metalcontaminated farm produce from an abandoned waste dump site. Metals could contaminate farm produce during pre- and post-harvest periods. The metal (zinc, copper, chromium, iron, manganese and cobalt) contents of Capsicum annum, Capsicum chinens and Capsicum frutescens pepper samples (harvested from an abandoned waste dump site in Gbarantoru in Bayelsa State) were determined and compared with WHO permissible levels. The pepper samples were crispy-dried, ground to fine powder, and digested with an acid mixture of sulphuric acid, perchloric acid and nitric acid in the ratio of 1:4:40. Prepared samples were analyzed using flame atomic absorption spectrophotometer. The results showed a wide range of concentrations: Capsicum annuum (Zn = 40.28 mg/kg, Cu = 4.17 mg/kg, Cr = 3.32 mg/kg, Fe = 105.23 mg/kg, Mn = 0.54 mg/kg, Co = 0.69 mg/kg), Capsicum chinens (Zn = 54.48 mg/kg, Cu = 4.22 mg/kg, Cr = 2.81 mg/kg, Fe = 158.33 mg/kg, Mn = 0.66 mg/kg, Co = 0.73 mg/kg), Capsicum frutescens (Zn = 47.45 mg/kg, Cu = 4.36 mg/kg, Cr = 3.20 mg/kg, Fe = 63.13 mg/kg, Mn = 0.59 mg/kg, Co = 0.77 mg/kg). The metal concentrations of the three hot pepper samples were found to be below WHO- permissible limits except for zinc in Capsicum chinens, which was found to be higher than the permissible limit. These species of pepper grown in this abandoned waste dumpsite are safe for food as stipulated by WHO.

Keywords: Metals, pepper, flame, atomic absorption, waste, dumpsite.