Determination of cadmium and lead in urine by flame atomic absorption spectrometry after activated carbon enrichment

Abstract

In this study, ammonium pyrrolidine dithiocarbamate was used as a complexing agent in the enrichment step for the determination of cadmium and lead in urine. The recoveries were above 90 % and the factors effecting recoveries, such as sample preparation, pH, amount of activated carbon, complexing reagent and the contact time,were studied. The interference effects from matrix components were compared after activated carbon enrichment. The calibration graphs were rectilinear for a range 1.2-80 μg 1^-1 and 1.6-53 μg 1^-1 for cadmium and lead, respectively. The relative standard deviations of the measurements (n=9) at concentration of 20 μg 1^-1 were 3 % for cadmium and lead. Detection limits ,defined as 3 s of blanks were 1.2 μg 1^-1 for cadmium and 1.6 μg 1^-1 for lead. The untreated urine (300 ml) was adjusted to pH 6 and 4 ml of 2% APDC solution were added to complex the metals. The mixture was stirred with 500 mg activated carbon for 40 min and next was filtered. The metals were leached with nitric acid.