Direct determination of cadmium and zinc in sea water by carbon furnace atomic-absorption spectrometry

Abstract

A simple and rapid method is described for the determination of cadmium and zinc in sea water, using atomic-absorption spectrometry with carbon furnace atomisation. Samples, diluted 1 + 1 with de-ionised water, are injected into the carbon furnace and atomised in an HGA-72 furnace atomiser under gas-stop conditions. A low atomisation temperature of 1492 °C is used to separate the atomic-absorption signals from background absorption. Detection limits (2σ) of 0.04 µg l^–1 for cadmium and 1.7 µg l^–1 for zinc are reported. These limits appear to be adequate for all but the cleanest sea water samples. The use of standard addition is essential because of the interference from magnesium chloride and also when samples of varying salinity have to be analysed.