Analysis of acetic acid extraction solutions by inductively coupled plasma mass spectrometry for the classification of solid waste

The direct analysis of acetic acid solutions in order to carry out waste classification by ICP-MS was investigated. Solid waste was leached with acetic acid solutions according to normalized procedures aiming at the determination of Ag, As, Ba, Cd, Cr, Pb and Se. Optimization of the ICP-MS instrumental parameters in extraction solutions was carried out. The formation of oxides and doubly charged ions was evaluated. Optimization of the RF power and nebulizer gas flow rate was also carried out. The procedure was applied to retorted shale, which was classified as a non-hazardous waste. In addition to ICP-MS, HR-CS F AAS was used for the analysis of the same samples. Accuracy of both techniques was verified by recovery tests. Precision, reported as RSD, was better than 3.6%. Both techniques could be used for solid waste classification, but ICP-MS allowed the determination of most of the elements in the extracts, whereas all the results obtained by HR-CS F AAS were below the detection limits. The developed procedure eliminates the need for digestion of the leachate, as required in one of the normalized procedures. The developed methods proved to be accurate, simple and fast for multielemental analyses and efficient for waste residue classification.