Online coupling electrochemical preconcentration and GFAAS technique as effective method for determination of ultratrace concentrations of antimony in groundwater and surface water samples


Abstract: The present article describes a method of determination of low antimony concentrations using a graphite furnace AAS technique after electrochemical preconcentration. A 2-electrode flow-through cell was developed with a working electrode made of gold-coated porous carbon and an accessory Pt electrode. This cell worked in online coupling with the graphite furnace atomizer. Accumulation occurred from the 6 M hydrochloric acid solution and 2 M nitric acid was used to dissolve and transport antimony into the sampling loop. The sampling loop was placed on a 6-way valve. The preconcentrated solution was transported to the atomizer using an air jet. The detection limit (3$\sigma )$ was 0.02 $\mu $g/L and the overall linear range was 0.05-10 $\mu $g/L. The method could be used only to determine the concentration of total inorganic antimony. The method was validated through analysis of certified reference materials and various water samples. Good agreement with the reference values was observed in all cases.

Keywords: Electrochemical preconcentration, antimony, flow-through system

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