Studies on microwave digestion procedures for the simultaneous multielement determination of arsenic, antimony, chromium, cadmium, nickel, and lead in municipal waste incineration fly ash by ICP-AES

Microwave digestion (MWD) with two kinds of acid mixtures (HCl-HNO3-HF, HClO4-HNO3-HF) was investigated for the simultaneous determination of six toxic elements (arsenic, antimony, chromium, cadmium, nickel, lead) in municipal-waste incineration fly ash (MWIFA) using inductively coupled plasma atomic-emission spectrometry (ICP-AES). The present investigated method was applied to the analysis of two certified reference materials (BCR No. 176, NIST 1633b); further the analytical results were compared with those obtained by alkaline fusion with LiBO2 .2H2O. The analytical results by MWD with an acid mixture of HCl-HNO3-HF were in good agreement with both certified and reference values for five elements, except for chromium, which requires a further alkaline fusion step for its complate recovery. The results by MWD with HClO4-HNO3-HF were in good agreement for all six elements with both certified and reference values, and comparable to those obtained by the standard alkaline fusion method. MWD with HClO4-HNO3-HF is, therefore, suitable for the rapid and simultaneous determination of these elements contained in MWIFA by ICP-AES, and has been successfully applied to the analysis of actual samples.