Non-volatile vanadium determination in petroleum condensate, diesel and gasoline prepared as detergent emulsions using GF AAS

The development of a procedure for non-volatile vanadium determination in petroleum derivative products by graphite furnace atomic absorption spectrometry (GF AAS) using sample preparation as detergent emulsion is presented. Emulsions of samples were make using concentrate nitric acid, Triton X-100, samples and water in the proportions of 1/1/2/6 respectively. Doehlert design was applied as experimental matrix to optimize the temperature program. A comparative study among the slopes of some analytical curves built in aqueous, surfactant and organic media and by analyte addition in several sample emulsions (diesel, gasoline and condensate) shows that a unique solution of surfactant in acid media can be used to make the calibration solutions. The developed procedure allows the determination of non-volatile vanadium in these samples with limit of detection (LOD) and limit of quantification (LOQ) of 14 and 45 mu g L-1, respectively. Precision, expressed as relative standard deviation (% RSD, n = 10) for 20 and 80 mu g L-1 were 6.4-2.9%, respectively. The proposed procedure was applied in the determination of vanadium in samples of petroleum condensate, gasoline and diesel. Accuracy was evaluated by spike tests in the analyzed samples. Results of recovery between 90% and 105% show that it can be successfully applied to this kind of samples. (C) 2007 Elsevier Ltd. All rights reserved.