Simultaneous Speciation of Iron(II) and Iron(III) by Ion Chromatography with Chemiluminescence Detection

Abstract

This study reports on a method for the speciation of iron in aqueous samples by the simultaneous analysis of divalent and trivalent iron ions with ion chromatography equipped with chemiluminescence detection (IC-CLD). Ferrous and ferric ions are first chelated by pyridine-2,6-dicarboxylic acid (PDCA) to form complexed anions, and separated by a mixed-bed ion-exchange column. The separated complexed ions are then detected with a CLD system containing luminol and hydrogen peroxide in a basic solution. This luminescence system has a linear dynamic range of ca. 3 orders of magnitude, with method detection limits as low as 7 μg L -1 for Fe(II) and 3 μg L -1 for Fe(III), measured in the simultaneous detection mode. This system resists interferences from common cations such as Cd, Ca, Cr, Cu, Mg, Ni, Pb, and Zn. Evaluation by analyzing real samples shows that this method is rapid, accurate, sensitive, and selective.

Luminol-Based Chemiluminescent Signals: Clinical and Non-clinical Application and Future Uses

“…CL emission was observed when azoxystrobin was injected into a mixture of luminol and KMnO 4 [137]. A method named ion chromatography equipped with CL detection (IC-CLD) method was used for the speciation of iron in aqueous samples by the simultaneous analysis of divalent and trivalent iron ions [138]. …”

Sensing materials developed and applied for bio-active Fe3+ recognition in water environment

“…1b). The 1:1 30 stoichiometry of the sensor-Fe 3+ complex resulted in the change of the fluorescence intensities were linear to Fe 3+ concentrations from 5.0×10 -6 to 1.0 ×10 -7 M with a detection limit of ca. 5.0×10 -8 M (~3 ppb).…”

“…2b). Due to the regulation of intramolecular charge transfer (ICT) between the sensor and Fe 3+ , the sensing system expressed nice ratiometric response, with the fluorescent spectra 30 significantly red-shift from 390 nm to 522 nm with the emission ratio value (I 522 /I 390 ) 2362-fold enhanced in the presence of Fe 3+ . Such a larger and stronger red-shift made the two emissions resolve quite well for accurate measurement and a large ratiometric value.…”

“…Dwivedi, et al, 44 designed a novel anionic polyfluorene derivative containing sulfate as terminal groups for selectively detecting Fe 3+ under physiological conditions. The sulfate terminated side chains were used to associate with oppositely charged Fe 3+ , which facilitated the efficient transfer from excited- 30 state CPs to Fe 3+ , resulting in high fluorescence quenching with a detection limit of 2.0×10 -7 M. These significant and unique properties of anionic CPs will certainly inspire fundamental development of conjugated fluorescent polymers as amplifying fluorescent signal in clinical applications. Wu, et al, 45 further 35 prepared a CPs-based thin film for sensing Fe 3+ by covalently immobilizing phosphonate-functionalized polyfluorene on glass surface.…”

“…While 25 excess iron could accelerate producing reactive oxygen species, which will deteriorate lipids, nucleic acids and proteins conversely. [4][5][6] Iron concentration is therefore an important parameter for water environmental quality and so the World Health Organization accordingly recommends 0.3 mg/L as the 30 upper concentration limit of iron in drinking water. 7 However, with the rapid development of modern industry and mineral industry, the amounts of iron in water environments are often changeable and getting quite different, routinely released from dissolution processes of iron-stones in nature and partially from 35 the corrosion processes in pipes.…”