Description
This method describes quantitative determination of the metals: lead, cadmium, zinc, copper and iron in various types of foods, with the exception of oils, fats and extremely fatty products. The method employs atomic absorption spectrophotometry (AAS) after microwave oven digestion under pressure. The method has been tested on dry materials only, but may under certain conditions be used for samples containing water. The sample is wet digested with nitric acid and hydrogen peroxide in a sealed container heated by microwaves. The sample solution is diluted with water and the concentrations of the metals are determined by flame or graphite furnace AAS.
Collaborative study: https://doi.org/10.1093/jaoac/83.5.1189
RSDR for results above the detection limit, ranged from 59% at 0.155 mg/kg to 16% at 1.62 mg/kg for Pb, from 28% at 0.0124 mg/kg to 11% at 0.482 mg/kg for Cd, from 9.3% at 35.3 mg/kg to 1.7% at 147 mg/kg for Zn, from 39% at 0.241 mg/kg to 3.0% at 63.4 mg/kg for Cu, and from 17% at 7.4 mg/kg to 5.9% at 303 mg/kg for Fe.
(Recommended by Codex as type III method)