Direct determination of cadmium in urine using graphite furnace atomic absorption spectrometry with Zeeman-effect background correction

Abstract

A procedure is described for the direct determination of cadmium in human urine using graphite furnace atomic absorption spectrometry with Zeeman-effect background correction. Except for a straightforward 1 + 1 V/V dilution of samples with 1.5% nitric acid, no matrix modifier or sample pre-treatment was necessary, thus reducing the risk of contamination. The concentration of cadmium in urine was evaluated directly from a calibration graph prepared using a metal-spiked human urine pool. In this way the time-consuming method of standard additions was avoided, permitting an increased sample throughput (120–150 samples per day; 90 s per analysis) with minimal attention of the analyst. In routine use, the precision (both within day and day to day) and limit of detection were of the order of <10% and 0.05 µg l^–1 of Cd, respectively. The method is suitable for the biological monitoring of cadmium in the general population or in occupationally exposed persons.