An Atomic Absorption Spectrophotometric Method for the Determination of Trace Amount of Zinc in Canned Juices After lon Exchange Separation

Abstract

An atomic absorption spectrophotometric method is described for the determination of microgram quantities of zinc in canned juices. After sample digestion in concentrated nitric acid, the solution is evaporated till near dryness, and then a solution of 2 M HCl is added to form tetrachlorozinacate (II) ion. This acid solution, containing the zinc complex is passed through an ion-exchange column (anion exchange resin, chloride form, which is preconditioned by passing 1 M HCl solution). Zinc is eluted from the column with 0.01 M HCl solution. After evaporation to dryness, the residue is dissolved in 1% (v/v) HNO₃, and then atomized into an air-acetylene flame. The limit of detection of the method is 0.15 μg ml⁻¹ Zn. The analytical aspects of the proposed method, including the standard addition technique are discussed.

Key Words:

• Zinc determination
• atomic absorption spectrophotometry
• solvent extraction
• canned juices analysis