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

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 less than 10% and 0.05 micrograms l-1 of Cd, respectively. The method is suitable for the biological monitoring of cadmium in the general population or in occupationally exposed persons.