Determination of Zn(II) in alcohol fuel by flame atomic absorption spectrometry after on-line preconcentration using a solid phase extraction system

The method for the determination of zinc in alcohol fuel by flame atomic absorption spectrometry using a solid phase extraction system containing Moringa oleifera seeds as biosorbent material is described. The multivariate optimization of hydrodynamic variables was performed using a full factorial design (2 4 ) including the following factors: sorbent mass, preconcentration time, volume of eluent, sample flow rate, sample pH and eluent concentration. It was verified that the aforementioned factors as well as their conditions were statistically significant at the 95% confidence level. With the optimized conditions, the preconcentration factor and the limit of detection were estimated as 23 and 0.9 μg/L, respectively. The analytical curve was linear from 0 to up to 100 μg/L, with a correlation coefficient of 0.999. The developed method was successfully applied to alcohol fuel, and accuracy was assessed through recovery tests with results ranging from 96 to 100%.