Immobilized salen (N,N′-bis (salicylidene) ethylenediamine) as a complexing agent for on-line sorbent extraction/preconcentration and flow injection-flame atomic absorption spectrometry

The microcolumn of salen I (N,N'-bis (salicylidene) ethylenediamine) immobilized on surfactant-coated alumina has been used for on-line preconcentration of copper and lead with a flow injection-flame atomic absorption spectrometry (FI-AAS). Various parameters affecting the deposition/elution processes in the FI-AAS system was optimized. Deposition of analytes was affected at pH of similar to 9, and injection of nitric acid (250 mu l 2 mol 1(-1)) served to elute retained species to AAS. A good relative standard deviation of 4.5 and 3.8% at 30 mu g 1(-1) (n = 7), high enrichment factors of 100 and 75, and detection limits of 0.3, 2.6 mu g 1(-1) (3S) for Cu(II) and Pb(II) were obtained, respectively. The method was applied to water samples, multivitamin tablet and standard reference alloys (C12E41 and C12X3500) and accuracy was assessed through recovery experiment and independent analysis by furnace AAS, or comparing the results with the accepted values. (c) 2005 Elsevier B.V. All rights reserved.