1984 Volume 33 Issue 9 Pages 500-503
A method is described for separation and concentration of trace amount (<20μg) of Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) coexisting with large amount of Ca(II), Mg(II), Na(I), and K(I) using chelating resin Unicellex B. The pH of sample solution obtained by digestion of food is adjusted to 5 in 0.1 mol dm-3 acetate buffer solution, then passed through the Unicellex B column for retention of heavy metals except Fe(III). Ca(II) and Mg (II), which were retained on the column at pH 5, are previously eluted with 0.5 mol dm-3 malate buffer solution(pH 5) and then heavy metals are eluted with 3 mol dm-3 HCl. Otherwise only Fe(III) and Cu(II) are retained on the column at pH 2 in 0.1 mol dm-3 maleate buffer solution and eluted with 3 mol dm-3 HCl. Heavy metals in the effluent are determined by Zeeman atomic absorption spectrophotometry. According to the procedure, 520μg of heavy metals in 1 dm3 of synthetic sample solution containing each 1 g of Ca(II), Mg(II), Na(I), and K(I) were quantitatively recovered in 10 cm3 of the effluent except Mn(II). The proposed method was applied to the determination of the heavy metals in NBS 1571 Orchard Leaves and some foods successfully.
