Preconcentration of molybdenum, antimony and vanadium in gasolsine samples using Dowex 1-x8 resin and their determination with inductively coupled plasma-optical emission spectrometry

Strong ion exchangers (Dowex 50W-x8 and Dowex 1-x8) were used for the separation and preconcentration of trace amounts of Mo, Sb and V in gasoline samples. Dowex 1-x8 resin was found to be suitable for the quantitative retention of these metal ions from organic matrices. The elution of the metal ions from Dowex 1-x8 resin was achieved by using 2.0 mol L-1 HNO3 solution. The Dowex 1-x8 preconcentration and separation method gave an enrichment factor of 120 with limits of detection equal to 0.14, 0.05 and 0.03 mu g L-1 for Mo, Sb and V, respectively. The limits of quantification were found to be 0.48, 0.18 and 0.10 mu g L-1 for Mo, Sb and V, respectively. Under optimized conditions, the relative standard deviations of the proposed method (n=20) were < 4%. The accuracy of Dowex 1-x8 preconcentration procedure was verified by the recovery test in the spiked samples of gasoline sample. The Dowex 1-x8 preconcentration method was applied to Conostan custom made oil based certified reference material for the determination of Mo, Sb and V. The results of the paired t-test at a 95% confidence level showed no significant difference. The separation and preconcentration procedure was also applied to the gasoline samples collected from different filling stations. (C) 2013 Elsevier B.V. All rights reserved.