DETERMINATION OF AS, CD, AND PB IN FEEDSTUFF BY GRAPHITE-FURNACE AAS

A method is described for the determination of arsenic, cadmium, and l ead in feedstuff using graphite furnace atomic absorption spectrometry (GFAAS) with stabilized temperature platform furnace conditions. An a cid digestion of the samples at controlled temperature was required pr ior to analysis. The absorbance readings of the acid digests were made after adding an appropriate chemical modifier. The determinations in the acid digests were performed in the linear range from 0.5-150 mu g/ L for As, 0.04-2.0 mu g/L for Cd, and 1.1-75 mu g/L for Pb. The validi ty of the method was verified by the standard additions method and by comparison of the results with certified reference material (Brown Bre ad CRM No. 191). The precision obtained was better than 14.5, 10.2, an d 10.3 for As, Cd, and Pb, respectively. The mean levels (mg/kg) obtai ned for As, Cd, and Pb in 73 feedstuff samples were 1.57 (0.52-3.01), 0.16 (0.04-0.86), and 0.65 (0.02-2.52), respectively.