Experimental design applied to the development of a copper direct determination method in gasoline samples by graphite furnace atomic absorption spectrometry

The aim of this work was to develop an experimental design to optimize the direct determination of copper in gasoline by graphite furnace atomic absorption spectrometry. The optimization of the process was carried out firstly by evaluating the variables in the procedure (pyrolysis time and temperature, atomization temperature and sample volume) using a factorial design (2(4)). The response surface was constructed and it presented pyrolysis optimal temperature on 800 degrees C, sample volume of 30 mu L, using the atomization temperature of 2500 degrees C. The amount of copper in the gasoline samples from Sao Luis City (Brazil) varied from 3.65 to 16.21 mu g L-1, with 0.65 and 1.9 mu g L-1 as detection limit and quantification limit, respectively. Accuracy was evaluated by a comparative procedure and the results proved the viability of copper direct determination in fuel samples. (C) 2008 Elsevier B.V. All rights reserved.