Potentiometric determination of copper in palm oil with a copper(II) ion-selective electrode

Abstract

The applicability of a copper(II) ion-selective electrode for the determination of the copper content of crude and hydrogenated palm oils was investigated. Dry ashing was used for destroying the organic matrix and a porcelain crucible was used as container. The recovery of copper in dry ashing and the leaching of copper from the internal glazing of a porcelain crucible were investigated. A complexing antioxidant buffer was used in order to minimise the interfering effect of iron(III) on the determination of copper(II). A direct potentiometric method can be applied to determine the copper content of palm oil at a concentration higher than 10 µg kg^–1 in the presence of 30 mg kg^–1 of iron.