Resumo

SILVEIRA, Eva Lúcia Cardoso; CALAND, Lília Basílio de; MOURA, Carla Verônica Rodarte de  e  MOURA, Edmilson Miranda. Determination of contaminants in used lubricating oils and in wastewater contamined by these lubricants. Quím. Nova [online]. 2006, vol.29, n.6, pp. 1193-1197. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40422006000600009.

A simple and reliable ashing procedure is proposed for the preparation of used lubricating oil samples for the determination of Zn, Fe, Pb, Ni and Cu by the flame atomic absorption spectrometry technique. Sulphanilic acid was added to oil samples, the mixture coked and the coke ashed at 550 ºC. The solutions of the ash were analysed by flame AAS for these metals. The quantification limits were 38.250 µg g^-1 for Zn, 4.550 µg g^-1 for Fe, 1.562 µg g^-1 for Pb, 1.450 µg g^-1 for Ni, and 0.439 µg g^-1 for Cu. The determinations, in lubricating oil, showed good precision and accuracy with recoveries between 90 and 110 %, indicating a negligible matrix effect in the experiments using addition of analyte, with relative standard deviation lower than 5%. The results for analysis of wastewater contamined by theses lubricants showed a very high relative standard deviation.

Palavras-chave : metal determination; lubricating oil; atomic absorption spectrometry.