Separation and preconcentration of metal ions and their estimation in vitamin, steel and milk samples using o-vanillin-immobilized silica gel

o-vanillin-immobilized silica gel has been used for the adsorption and esti mation of copper, cobalt, iron and zinc by both batch and column techniques . Metal ions were quantitatively retained on the column packed with immobil ized silica gel in the pH range 4.0-6.0 for Cu, 5.0-6.0 for Co, 4.5-6.0 for Fe and 6.0-8.0 for Zn. The distribution coefficient D determined for each metal was as follows (ml g(-1)): Fe, 5.4 x 10(2); Cu, 4.9 x 10(2); Zn, 4.4 x 10(2); Co, 3.8 x 10(2). Methods have been developed to estimate zinc, cop per and cobalt in milk, steel and vitamin samples, respectively. (C) 1999 E lsevier Science B.V. All rights reserved.