This work presents the determination of Co, Cu, Fe, Mn, Ni and V in diesel and biodiesel samples by ETV-ICP MS using emulsion sample preparation. The emulsion composition was: 1.0 g of the diesel or biodiesel sample, 2.0 mL of a 5% m/v Triton X-100 solution, 0.5 mL of HNO3 and deionized water to a 10 mL final volume. The optimized parameters were mass of carrier/modifier (1.0 microg Pd), RF power (1100 W), carrier gas flow rate (0.95 L min(-1)) and inner ETV gas flow rate (0.15 L min(-1)). The determinations were performed against aqueous solutions using 10 microg L(-1) Rh as internal standard. The accuracy of the method was verified through the analysis of the NIST 1634c reference residual fuel oil, recovery tests and comparison of the results with those obtained by GF AAS. The results were in agreement according to the t-test at a 95% confidence level. The RSD values were lower than 20%, the recoveries were between 80 and 120% and the LOD values were in the order of ng g(-1), showing the good accuracy and sensitivity of the method.

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Methods for the determination of As and Hg by vapor generation atomic spectrometry in acetic acid leachates are proposed. The waste classification involves several tests, including the toxicity evaluation by which the solid waste is leached with acetic acid solutions according to procedures specified by Norms as for example USEPA, toxicity characteristic leaching procedure (TCLP). Some elements, such as As and Hg, are determined in the leachate, and if the concentration is higher than the limits of the Norms the waste is classified as hazardous. In this study, two wastes, a retorted shale and a catalyst from hydrothermal treatment, were submitted to the procedures. The reagents concentrations used to generate arsine for further determination by hydride generation atomic absorption spectrometry (HG AAS) were optimized: HCl (5% v/v), KI (3% m/v) and NaBH 4 (1.0% m/v containing 0.1% m/v NaOH). The previous addition of KI to reduce As(V) to As(III) was necessary to obtain accurate results. Mercury was determined by two techniques, cold vapor atomic absorption spectrometry (CV AAS), using NaBH 4 as reducing agent, and cold vapor atomic fluorescence spectrometry (CV AFS), using SnCl 2 as reducing agent. The reagents concentrations were also optimized, for AAS: HCl (0.5% v/v), KMnO 4 (0.25% m/v), hydroxylamine hydrochloride (0.02% m/v) and NaBH 4 (0.5% m/v containing 0.1% m/v NaOH); and for AFS: HCl (2% v/v), KMnO 4 (0.04% m/v), hydroxylamine hydrochloride (0.02% m/v) and SnCl 2 (3% m/v). Addition of KMnO 4 was used for an efficient vapor generation in the presence of acetic acid. The detection limit (3 s, n = 10) for Hg using CV AFS was about two orders of magnitude lower than for CV AAS. All three proposed methods can be used for waste classification, considering that the limits of detection were in the order of ng L − 1 , much lower than the concentration limits of the Norm EPA, 5 mg L − 1 for As and 0.2 mg L − 1 for Hg. Accuracy for As was demonstrated by comparison with the results obtained by ICP-MS, and for Hg it was demonstrated by the recovery test. The results by CV AAS were below the detection limit. The analytes concentrations in the acetic acid leachates from both residues were below the concentration limits of the Norms, demonstrating that they are non-dangerous concerning As and Hg.

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A review on inorganic and organic contaminants in biodiesel used as fuel is presented. The main contaminants normally present in biodiesel that may affect the final product quality are discussed. The possible sources, as well as the effects of the contaminants in the production process, in the biodiesel stability and in its performance in the motor as fuel are also discussed. The criterions for the quality control of biodiesel and the limits established by the regulator agencies are described. In addition, a brief discussion on the main analytical techniques used for monitoring inorganic and organic parameters, is presented.

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