Indirect determination of zirconium in microgranite samples by atomic absorption spectrometry

Abstract

An indirect method for the determination of zirconium in microgranite rock samples by atomic absorption spectrometry (AAS) is described. Zirconium forms a stable ion associate, Zn²⁺[ZrF₆]^2–, in acidic solution that can be extracted into chloroform with an efficiency greater than 99.5%. The extract can be analysed for Zn (and hence indirectly for Zr) by AAS after stripping back into an aqueous phase containing 4 M HCl. The limit of detection by this method is 42 ng ml^–1, equivalent to a limit of determination in the rock of 1.1 µg g^–1. The calibration graph is linear up to 2.25 µg ml^–1 of Zr. Large numbers of foreign ions do not interfere. The method was applied successfully to the determination of Zr in microgranite samples from Mayurbhanj (India).