Simultaneous flow-injection determination of iron(II) and total iron by micelle enhanced luminol chemiluminescence

摘要

A flow-injection method is proposed for the determination of iron(II) and for the simultaneous determination of iron(II) and total iron based on the catalytic effect of iron(II) on the oxidation of luminol with hydrogen peroxide in an alkaline medium. The activating effect for the catalysis of iron(II) was extremely exhibited in the presence of citric acid, while citric acid acted as a masking agent for iron(III). Furthermore, the sensitivity of the method was enhanced by adding tetradecyltrimethylammonium bromide (TTAB) as a cationic surfactant together with citric acid. The iron(III) in sample solution can be determined by passing through the silver reductor column introduced in the FIA system to reduce iron(III) to iron(II), which allows total iron determination. Calibration graphs for iron(II) and total iron were linear over the range 5x10(-9)-1x10(-6) mol dm(-3) at a rate of 18 samples h(-1) (36 peaks h(-1)). The relative standard deviations (n=10) for 4x10(-8) mol dm(-3) iron(II) and 1x10(-7) mol dm(-3) total iron were 3.0% and 1.5%, respectively. The proposed method was successfully applied to the determination of iron in human hair (NIES, no. 5) and natural waters. (C) 1998 Elsevier Science B.V. All rights reserved. [References: 26]