The determination of zinc in water by flame atomic absorption spectrometry after its separation and preconcentration by malachite green loaded microcrystalline triphenylmethane

A new method for the separation and preconcentration of zinc using microcrystalline triphenyl methane loaded with malachite green was developed prior to the determination by FAAS. The effects of different parameters, such as the amounts of malachite green, NH4SCN and triphenyl methane, stirring time and various metal ions on the enrichment yield of zinc have been studied to optimize the experimental conditions. Under the optimum conditions, zinc can be adsorbed on the surface of microcrystalline triphenyl methane loaded with malachite green. The possible reaction mechanism for the preconcentration of zinc was discussed in detail in this paper. Zn(II) can be completely separated from Pb(II), Ni(II), Co(II), Cd(II), Mn(II), Cr(III), Cu(II), Fe(III) and Al(III) in the solution. The detection limit of this proposed method for zinc is 0.05 mu g L-1 with preconcentration factor of 200. The recovery is in the range of 96.5-105%. The relative standard deviation is 1.0-3.1%. Analytical results obtained with this novel method are very satisfactory. The proposed method was successfully applied to the determination of trace zinc in various water samples by FAAS after preconcentration using microcrystalline triphenyl methane. (c) 2006 Elsevier B.V. All rights reserved.