Evaluation of a novel PTFE material for use as a means for separation and preconcentration of trace levels of metal ions in sequential injection (SI) and sequential injection lab-on-valve (SI-LOV) systems: Determination of cadmium(II) with detection by electrothermal atomic absorption spectrometry (ETAAS)

Abstract

The operational characteristics of a novel poly(tetrafluoroethylene) (PTFE) bead material, granular Algoflon®, used for separation and preconcentration of metal ions via adsorption of on-line generated non-charged metal complexes, were evaluated in a sequential injection (SI) system furnished with an external packed column and in a sequential injection lab-on-valve (SI-LOV) system. Employed for the determination of cadmium(II), complexed with diethyldithiophosphate (DDPA), and detection by electrothermal atomic absorption spectrometry (ETAAS), its performance was compared to that of a previously used material, Aldrich PTFE, which had demonstrated that PTFE was the most promising for solid-state pretreatments. By comparing the two materials, the Algoflon® beads exhibited much higher sensitivity (1.6107 μg l-1versus 0.2956 μg l-1per integrated absorbance (s)), and better retention efficiency (82% versus 74%) and enrichment factor (20.8 versus 17.2), although a slightly smaller linear dynamic range (0.05-0.25 μg l-1versus 0.05-1.00 μg l-1). Moreover, no flow resistance was encountered under the experimental conditions used. The results obtained on three standard reference materials were in good agreement with the certified values. © 2004 Elsevier B.V. All rights reserved.