Analysis of acetic acid extraction solutions by inductively coupled plasma mass spectrometry for the classification of solid waste Tatiane de A. Maranhão a, ⁎, Jessee S.A. Silva a,b , Vera L.A.F. Bascuñan a,1 , Fernando J.S. Oliveira c , Adilson J. Curtius a,1 a Departamento de Química, Universidade Federal de Santa Catarina (UFSC), 88040-900 Florianópolis, SC, Brazil b Instituto Federal de Santa Catarina (IFSC), 88020-300 Florianópolis, SC, Brazil c Petróleo Brasileiro S.A,Gerência de Meio Ambiente,Coordenação de Resíduos e Áreas Impactadas, Rio de Janeiro, RJ, Brazil abstract article info Article history: Received 20 October 2010 Accepted 29 October 2010 Available online 9 December 2010 Keywords: Solid waste Acetic acid Toxicity ICP-MS HR-CS F AAS 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. © 2010 Published by Elsevier B.V. 1. Introduction Metals are present in the ecosystems due to natural processes, mainly as constituents of minerals and soils, and due to anthropogenic actions, such as particle dispersion in the air by industrial emissions and the use of fertilizers [1]. Industrialization and urbanization resulted in a rapid increase in the concentration of toxic metals in the environment, which after release are integrated into the biosphere [2]. Since the industrial activities contribute significantly to the environmental impact, a responsible management of the natural resources, wastes, effluents and atmospheric emissions is of great importance. Solid waste containing metals and other elements may represent a serious problem because these elements may accumulate in soils in several different ways, such as water soluble extractable compounds or bounded to carbonates, iron-manganese oxides and organic compounds. The elements in the solid waste that are water-soluble and exchangeable fractions are considered bioavailable and are likely to be transported to water bodies and, as a consequence, can be absorbed by plants and may eventually enter the food chain [3,4]. Metal fractionation is an important aspect related to environ- mental issues, since the sole information regarding metal mobility and total concentration in soil does not provide sufficient data to evaluate the bioavailability of the metal [4–7]. Such erroneous evaluation may lead to errors concerning the assessment of environmental effects due to possible overestimation of the exposure risks, which consequently increases the management costs [6]. For environmental purposes, a matter of primary interest concerns the amount of bioavailable pollutants in the soil, which reflect how much this fraction, that usually represents only a small fraction of the total, influences the environment, plant growth and the water and soil quality [8,9]. Most of the procedures used to classify solid wastes and assess the metal solubility and bioavailability are carried out by extraction to an organic medium. In Brazil, the Brazilian Association of Technical Norms (ABNT), by means of the Brazilian Norm (NBR) number 10005:2004 [10] regulates the procedures to obtain waste leaching extract in order to classify it as hazardous or non-hazardous. The leaching procedure of the Brazilian Norm is identical to that of the Environmental Protection Agency (EPA) Method 1311 [11] (Toxicity Characteristic Leaching Procedure, TCLP) and also refers to EPA SW 846 (Test Method for Evaluating Solid Waste). The test takes into account the ability of organic and inorganic compounds to be transferred from the waste to an extraction medium. Two extracting solutions containing glacial acetic acid at 0.57% v/v and maintained at Microchemical Journal 98 (2011) 32–38 ⁎ Corresponding author. Tel.: + 55 48 37216841; fax: + 55 48 37216850. E-mail address: tatiane.maranhao@gmail.com (T. de A. Maranhão). 1 INCT de Energia e Ambiente do CNPq, http://www.inct.cienam.ufba.br. 0026-265X/$ – see front matter © 2010 Published by Elsevier B.V. doi:10.1016/j.microc.2010.10.007 Contents lists available at ScienceDirect Microchemical Journal journal homepage: www.elsevier.com/locate/microc