Flow Injection Solid Phase Extraction for Trace Metal Determination Using a Chelating Resin and Flame Atomic Absorption Spectrometry Detection

Abstract

The development of a simple and sensitive on-line flow injection preconcentration system is reported using a polyamino-polycarboxylic acid chelating resin for the automated determination of cadmium(II), chromium(III), copper(II), and lead(II) in natural waters and urine by flame atomic absorption spectrometry (FAAS). The adsorbent showed a high sorption affinity for the metal ions at pH values from 5.0 to 6.0. The retained analytes were efficiently eluted by 1.5 mol/L HNO3. The effect of chemical and hydrodynamic parameters such as pH, selection of eluent (type, volume and concentration), and sample/eluent flow rates were studied, providing optimum conditions for the analysis of real samples. For a preconcentration time of 120 sec, the sampling frequency was 22/h and the enhancement factors were 105, 49, 106, and 98 for cadmium(II), chromium(III), copper(II), and lead(II), respectively. The detection limits were between 0.1 and 1.6 mg/L, while the precision was less than 3.3% as the relative standard deviation for all metal ions. The accuracy of the method was evaluated by the analysis of certified reference materials and fortified environmental and biological samples.