Determination of Cadmium by Inductively Coupled Plasma Atomic Emission Spectrometry after Suction-Flow On-Line Preconcentration on 8-Quinolinol-Loaded Active Carbon

Abstract

The suction-flow on-line column preconcentration of cadmium from an aqueous solution for inductively coupled plasma atomic emission spectrometry (ICP-AES) was investigated utilizing a column packed with gas chromatographic-grade porous active-carbon impregnated with 8-quinolinol. A sample solution (pH 2.5-7) and a buffer solution were sucked, mixed and pumped through the column; subsequently, the analyte was eluted directly into the nebulizer of the ICP with 1cm3 of 0.5mol dm-3 hydrochloric acid. Using 5cm3 of the sample solution, this method gave a signal enhancement of 1 order of magnitude for cadmium, better than that obtained by a conventional nebulization system; the detection limit was 0.25ng cm-3 with a sampling rate of 35h-1. The relative standard deviation for 500ng cadmium was 1.1% (n=10). This column could be used for more than 80 replicate analyses when 5cm3 of a standard solution containing 100ng cm-3 cadmium(II) was introduced into the system each time. The proposed method was applied to the determination of cadmium in certified biological reference materials.