Studies on the determination of cadmium in blood by furnace atomic non-thermal excitation spectrometry

Abstract

Cadmium atomic emission can be detected in a FANES low-pressure Ar discharge at atomiser temperatures as low as 140 deg;C when the analyte is present as CdCl₂. Cadmium chloride molecules vaporised at this temperature are dissociated by electron impact in the discharge, giving a substantial Cd atom concentration before thermal dissociation of the molecules becomes feasible. This results in a 100-fold greater tolerance towards chloride matrix chemical interferences than encountered for Cd in ETA-AAS with tube-wall atomisation. However, the determination of cadmium in deproteinised whole blood by FANES is not totally interference free and a standard additions procedure is required to give an accurate determination. The FANES instrument detection limit for Cd was calculated to be 0.04 µg l^–1. For the deproteinisation procedure applied, the detection limit for cadmium in whole blood was 0.2 µg l^–1.