DETERMINATION OF NICKEL IN VEGETABLE MATRICES BY ATOMIC-ABSORPTION SPECTROMETRY AFTER PRECONCENTRATION ON ACTIVATED CARBON

An enrichment method has been optimized for the determination of Ni in vegetable samples of food origin. Dry ashing and wet ashing methods h ave been used for digestion of the samples tested and these two decomp osition methods were compared. Nickel was determined by flame atomic a bsorption spectrometry. For the enrichment procedure, cupferron and ox ine were examined as complexing reagents in the pH range 2.0-9.5 and t he chelate formed was adsorbed on the activated carbon. The parameters affecting Ni recovery such as amount of cupferron, amount of activate d carbon and stirring time were investigated. Interferences were exami ned and interference from Mg was overcome by this optimized enrichment method. The relative standard deviation was found to be 3 % for the N i concentration of 80 mu g L-1. Results for the determination of Ni in various vegetables are given.