Determination of cadmium in whole blood and urine by electrothermal atomic absorption spectrometry using palladium-based modifers and in situ decontamination

Abstract

The determination of Cd in whole blood and urine by electrothermal atomic absorption spectrometry using Pd-based modifiers and in situ decontamination was studied. The performance of Pd, Pd + NH₄NO₃, and Pd + Mg(NO₃)₂ as modifiers were compared with respect to maximum pyrolysis and atomization temperatures, background attenuation, linear calibration range and matrix interference. Samples were diluted (1 + 4) with 0.1% Triton X-100 (blood) or 0.2% HNO₃(urine), and introduced onto the graphite tube platform already containing the in situ dried and decontaminated modifier. The influence of modifier volume and concentration, as well as that of the dilution ratio was investigated. The proposed procedure involves the use of Pd(NO₃)₂+ Mg(NO₃)₂ as modifier, a pyrolysis temperature of 700 °C and an in situ decontamination step of 1200 °C. The atomization temperature was 1700 °C. The detection limit (n= 10, k= 3) was 0.22 µg l^–1 for both samples. Typical relative standard deviation values (n= 3) were below 3%. Using matrix-matched standards, good agreement was observed between experimental and reference values in the analysis of certified reference materials. Interlaboratory comparison data have confirmed the validity of the proposed analytical procedure.