Flow injection potentiometric determination of Fe(III) using a fluoride-selective electrode as detector

Abstract

Flow injection analysis (FIA) system incorporating a fluoride ion-selective electrode (FISE) as detector is described. Laboratory-built cascade flow cell equipped with FISE and reference electrode is used for flow injection potentiometric determination of Fe(III) based on monitoring of the formation of FeF 2 + in acid solution. Under optimized flow conditions (4.0 mL min -1 , 300 L samples, 10 -5 mol L -1 sodium fluoride in the carrier stream) a rectilinear calibration graph is obtained by plotting the peak height versus concentration of iron in the range of Fe(III) concentration from 1 10 -4 to 1 10 -1 mol L -1 in a 0.01 mol L -1 perchloric acid or acetate buffers (pH 2.8; 3.4).