Abstract

MACHUCA, MARIA ALICIA; DE GREGORI, IDA  and  PINOCHET, HUGO. DETERMINACION AMPEROMETRICA INDIRECTA DE Se(IV) CON PRECONCENTRACIONEN LINEA POR ANALISIS DE INYECCION EN FLUJO. Bol. Soc. Chil. Quím. [online]. 2000, vol.45, n.1, pp.99-107. ISSN 0366-1644.  http://dx.doi.org/10.4067/S0366-16442000000100014.

The experimental conditions for the indirect amperometric detection of Se(IV) by flow injection analysis have been optimized. The method is based on the Se(IV) reduction to Se(0) in acid medium in presence of anexcess of iodide, being generated yotrion species which is electroactive and amperometrically detected at vitreous carbon electrode. The signal depends on the quantity of Se(IV) in the samples. Under optimized conditions,analytical conditions of the method were determined. The detection and quantification limits were 4.8 µg l^-1 and 15.9 µgl^-1, respectively. Because of the method proposed for its applicationto the determination of Se(IV) in natural water samples, it became necessary to increase the detection sensitivity and an on-line concentration stagewas coupled. This stage is carried out on an anionic resin exchange (Dowex1-X8). The detection and the quantification limits were in this case 0.06µg l^-1 and 0.2 µg l^-1, respectively.The on- line preconcentration stage increases the sensibility of the amperometricdetection which allows the Se(IV) determination at µg l^-1levels

Keywords : Determination of Se(IV); flow injection analysis; amperometric detection; on-line preconcentration; natural waters.