Abstract
In the present work, multiwalled carbon nanotubes (MWCNTs) a solid phase extraction sorbent has been described for the preconcentration of trace amounts of some heavy metals in water samples prior to their determination by flame atomic absorption spectrometry. The effect of different parameters has been thoroughly studied and applied the optimum experimental conditions. The calibration was performed using aqueous standard solutions with an enrichment factor of the preconcentration was 10. The calibration graphs were linear with the correlation coefficient range 0.9994-0.9999 under the optimized conditions. The developed method was then applied for the determination of copper, cadmium, chromium, zinc and iron in water samples by flame atomic absorption spectrometry (FAAS). The detection limits under these conditions were 5.46, 2.97, 5.0, 0.96, and 7.94 mu g L-1 for Cu, Cd, Cr, Zn and Fe, respectively. The relative standard deviations (RSDs) for five replicate samples were found to be less than 3.0%. The percentage recoveries of metals in spiked samples were found to be in the range of 90.5%-99.0%. The standard reference materials (NIST SRM 3108, 3112a, 3114, 3126a, and 3168a) were used to verify accuracy of this method. This procedure was successfully applied to the determination of these metals in water samples with satisfactory results and recommended to apply in all desalination plants samples.