On-line preconcentration of zinc on ethyl vinyl acetate prior to its determination by CVG-ICP-OES

Abstract

A separation/preconcentration procedure using solid phase extraction coupled to zinc vapor generation associated to inductively coupled plasma optical emission spectrometry determination in water samples was studied. The solid phase material was ethyl vinyl acetate (EVA) contained in a column, where the analyte ions were retained without using any complexation agent. The variables involving the preconcentration and the chemical vapor generation (CVG) were optimized using both full factorial and central composite designs, respectively. Volatile species of zinc were generated by merging the acidified eluent and sodium tetrahydroborate in a continuous flow system. The gaseous analyte was introduced via a stream of Ar carrier into the inlet tube of the ICP torch. An enhancement factor of 230-fold for a sample volume of 16 mL was obtained. The detection limit was 0.06 μg L− 1. The proposed method was successfully applied to the determination of traces of zinc in a Certified Reference Material and tap and river water samples.