Sensitive Determination of Iron Using Disposable Nafion-Coated Screen-Printed Graphite Electrodes

Abstract

Iron was determined in drinking water using low-cost, disposable, and highly reproducible modified graphite screen-printed electrodes. Nafion is a chemically inert polymer and endows remarkable sensitivity for Fe(III) through interaction with the sulfonic groups on the polymer surface. The concentration of Nafion on the modified electrodes was optimized and the best results were obtained using 2 μL of 0.2% Nafion in ethanol. The preconcentration of analytes was performed in an electrodeless mode with stirring in 0.01 mol L−l HCl. Under selected conditions and for a preconcentration time of 60 s, square-wave voltammograms exhibited a cathodic peak, the height of which was linearly dependent on the concentration of iron from 0.05 to 5.00 µmol L−l. The limit of detection was 15 nmol L−l Fe(III). The developed electrodes were successfully used to determine iron in tap water. Accuracy of the method was evaluated with recovery measurements in spiked samples. The values were 108 ± 3%. Possible interferences from the coexisting ions were also investigated. The results show that the sensors are sensitive, selective, rapid, reliable, and suitable for the determination of Fe(III) in water.