Determination of urinary cobalt using matrix modification and graphite furnace atomic absorption spectrometry with Zeeman-effect background correction

Abstract

Cobalt in human urine was determined using graphite furnace atomic absorption spectrometry with Zeeman-effect background correction. Magnesium nitrate and nitric acid were used as matrix modifiers. Except for a 1 + 1 dilution, no sample pre-treatment was necessary; this permitted a direct determination. Hence, the risk of sample contamination was reduced and sample throughput was increased. A single urine calibration graph was constructed from which all calculations were made in a single analytical run. In this way, the need for the method of standard additions was eliminated. A detection limit of 2.4 µg l^–1 permits the determination of potentially toxic levels of cobalt in human urine.