Different Approaches for Digestion, Performance Assessment and Measurement Uncertainty for the Analysis of Cadmium and Lead in Feeds

Certain feedingstuffs are sources of contamination for animals with cadmium (Cd) and lead (Pb). Different approaches for sample digestion, performance assessment, and measurement uncertainty for the analysis of Pb and Cd by flame atomic absorption spectrometry were compared. Full method validation, including matrix effect and analytical limits, were assessed. Despite having a lower performance compared to the microwave digestion, dry ashing was a viable alternative for sample digestion, leading to lower operating costs. Interlaboratory validation proved to be a cheaper alternative, instead of the long traditional in-house approach. The method was suitable for routine analysis of several feed samples. There was a greater amount of quantifiable results for Pb, ranging from traces up to high concentrations (7430 ± 930 mg kg-1). Cd was also quantified in some samples, ranging from 0.11 ± 0.01 to 8.71 ± 0.90 mg kg−1. The higher concentrations of both metals were found in mineral mixtures and fish meal.