Flow injection system for cadmium preconcentration on poly(octadecyl diitaconate) (PDI-18) and atomic absorption spectrometry detection

This work assesses the potential of a new adsorptive material: poly(octadec yl diitaconate) (PDI-18), for the preconcentration of cadmium traces. The p rocedure involves the formation of a neutral cadmium chelate with ammonium pyrrolidinedithiocarbamate (APDC) as chelating reagent, its adsorption on P DI- 18 minicolumns, and its elution with 300 mul of methyl isobutyl ketone. Using 20 mg of the sorbent material with a loading time of 2 min per sampl e, preconcentration factors of cadmium of 110 were readily achieved related to the direct introduction of aqueous solutions into an atomic absorption spectrometer. To evaluate the performance of this material, a flow injectio n system was used for samples of water from different sources, and the accu racy was assessed through recovery experiments and using certified referenc e materials. All the analytical results obtained were in good agreement wit h the certified values. The linear range, the detection limit (3 sigma) and the relative standard deviation at 2 ng ml(-1) were 0.5-5.0 ng ml(-1), 0.0 8 ng ml(-1) and 2.1%, respectively. The effect of various ions on the deter mination of cadmium was investigated in order to evaluate the selectivity o f the new sorbent material. (C) 2001 Elsevier Science B.V. All rights reser ved.