Preconcentration of inorganic antimony(III) in environmental samples by PSTH-Dowex microcolumn and determination by FI-ETAAS.

A flow injection on-line sorption preconcentration system has been synchronously coupled to an electrothermal atomic absorption spectrometry (ETAAS) system for the selective determination of trace amounts of Sb(III) in water, soil and plant. The determination was achieved by selective complexation and sorption of Sb(III) with [1,5-bis(2-pyridyl)-3-sulphophenyl methylene thiocarbonohydarzide (PSTH) immobilized on an anion-exchange resin (Dowex 1x 8-200)] at a wide range of pH, quantitative elution with 50mul of 2M HNO(3) and subsequent ETAAS detection. ETAAS determination of the analyte was performed in parallel with the preconcentration of the next sample. Using a preconcentration time of 60s and a sample loading flow rate of 2.8mlmin(-1), an enhancement factor of 12 was obtained in comparison with direct injection of 50mul aqueous solution, resulting in a sampling frequency of 31samplesh(-1). The detection limit (3s) was 2mugl(-1) and the precision was 3.1% (R.S.D.) for 11 replicate determinations at 10mugl(-1). The accuracy of the proposed method was demonstrated by analyzing one certified sample and different spiked samples.