A Sensitive Method for Cadmium Determination Using an On-line Polyurethane Foam Preconcentration System and Thermospray Flame Furnace Atomic Absorption Spectrometry
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- TARLEY César Ricardo Teixeira
- Institute of Chemistry, Department of Analytical Chemistry, State University of Campinas-UNICAMP
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- ARRUDA Marco Aurélio Zezzi
- Institute of Chemistry, Department of Analytical Chemistry, State University of Campinas-UNICAMP
Abstract
A new sensitive and low cost method for cadmium determination at µg l-1 levels that combines an on-line preconcentration system with the thermospray flame furnace atomic absorption spectrometry technique (TS-FF-AAS) is described in this work. Cadmium is preconcentrated from an acidic medium (pH 2.0) by forming a complex with ammonium O,O-diethyldithiophosphate (DDTP), which is then adsorbed onto polyurethane foam (PUF). The elution step is performed by using 80% (v/v) ethanol. The effects of the chemical and flow variables associated with the preconcentration were studied, such as the pH of formation of the Cd-DDTP complex, the DDTP concentration, the preconcentration and elution flow rate and the mass of adsorbent. The present method was operated in volume-mode (2 ml) and provided a linear range from 0.4 to 15.0 µg l-1 with a sample throughput of 16 h-1. The increase of power detection related to TS-FF-AAS by coupling the preconcentration system was confirmed by the enhancement of sensitivity (ca. 5 times), when compared to the value for TS-FF-AAS alone, thus achieving a low detection limit (0.12 µg l-1). The accuracy of the method was confirmed from analyses of spiked water samples and by the use of a reference technique (ETAAS). Certified biological materials were also used for the same purpose.
Journal
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- Analytical Sciences
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Analytical Sciences 20 (6), 961-966, 2004
The Japan Society for Analytical Chemistry
