Use of a matrix modifier and L'vov platform in the determination of copper in pooled human saliva by electrothermal atomic absorption spectrometry

Abstract

The L'vov platform was used with a common matrix modifier, HNO₃ and NH₄NO₃, to eliminate matrix interferences present in saliva samples during the determination of copper by furnace atomic absorption spectrometry. The NaCl matrix effects were evaluated from a graph of the absorbances versus charring temperatures using a copper solution of 20 µg l^–1 with NaCl added. The results obtained by atomisation of the standard, either by tube or by L'vov platform, indicate that severe interferences are observed if the modifier is absent. Precision was improved by using a combination of platform, matrix modifier and standard additions techniques. The analysis of ten samples of pooled saliva gave an average of 16.7 ± 1.6 µg l^–1 of Cu and a recovery of 99 ± 1.6%. The sensitivity was increased from 0.1 ng (common tube) to <0.1 ng (L'vov platform tube).