ICP-AES Determination of Lead, Arsenic, Cadmium and Mercury in Lead Concentrates with Microwave Assisted Sample Digestion

The main element (Pb) and 3 poisonous and harmful elements (As, Cd and Hg) in lead concentrates were determined simultaneously by ICP-AES with microwave assisted sample digestion. 0.20 g of the sample in a digestion vessel was mixed with 9 mL of HNO3, 3 mL of HCl, 2 mL HBF4 and 2.5 mL of H2O2 successively; after covering the vessel tightly, the sample was digested in microwave digestor under the pre-set program. Analytical spectral lines of 220.351 nm for Pb, 189.042 nm for As, 228.802 nm for Cd and 184.950 nm for Hg were chosen for the analysis. Values of detection limits (3s) of Pb, As, Cd and Hg found were 16.0, 2.2, 0.4 and 0.8 μg·g-1 respectively. The proposed method was applied to the analysis of a CRM (GBW 07617) and a sample of lead concentrate. The results of the elements found in the CRM by the present method were in consistency with the certified values, while the results of elements found in the concentrate sample were checked quite well with the results obtained by AAS and AFS. Values of RSD′s (n=10) found were in the range of 0.15%-3.9%.