DETERMINATION OF TRACE ELEMENTS BY ATOMIC ABSORPTION SPECTROMETRY AFTER PRECONCENTRATION ON A FINELY DIVIDED ION-EXCHANGE RESIN

点击翻译按钮获取中文摘要

Graphite-furnace atomic absorption spectrometry is one of the most widely used techniques for the determination of trace elements in water. However, its sensitivity for cadmium and lead is not sufficient for a direct determination of these elements in drinking water. So far, many techniques have been used for the enrichment of trace elements in water samples. ^1 One of the most important conditions of the enrichment techniques is simple connection to the subsequent determination techniques.The aim of this work was to develop a simple preconcentration method for the determination of cadmium and lead in tap water with the combined use of a finely divided ion-exchange resin and ammonium pyrrolidinedithiocarbamate (APDC). Since the ion-exchange resin particles have both hydrophilic and hydrophobic properties, they can act as a hydrophilic organic solid in the bulk solution, and can extract species with hydrophobic pyoperties. Cadmium-and lead-APDC complexes were extracted simultaneously on the resin at pH 6. The resin particles holding the cadmium- and lead-APDC complexes were separated by filtration and dispersed in 1.0 ml of 0.1 mol 1<@D1-1@>D1 hydrochloric acid containing 100 mug of palladium (II). The resulting suspension was introduced directly into the graphite furnace by an automatic sampler. The detection limits of cadmium and lead in a 150-ml sample aliquot were 0.17 and 5.7 ng 1<@D1-1@>D1、respectively, based on three times the standard deviation of blank values. The proposed method was applied to the determination of cadmium and lead in the tap water supplied to our laboratory during the period from 9th to 18th September, 1997. The concentration of the metal ions for 10 days were 6.52(]SY.+-。[)0.75 ng 1<@D1-1@>D1 for cadmium and 136(]SY.+-。[)12 ng 1<@D1-1@>D1 for lead, respectively.<@D12@>D1