Iron speciation by microsequential injection solid phase spectrometry using 3-hydroxy-1(H)-2-methyl-4-pyridinone as chromogenic reagent

Abstract

The speciation of iron using the newly synthesized 3-hydroxy-1(H)-2-methyl-4-pyridinone by solid phase spectrophotometry in a microsequential injection lab-on-valve (µSI-LOV-SPS) methodology is described. Iron was retained in a reusable column, Nitrilotriacetic Acid Superflow (NTA) resin, and the ligand was used as both chromogenic and eluting reagent. This approach, analyte retention and matrix removal, enabled the assessment of iron (III) and total iron content in fresh waters and high salinity coastal waters with direct sample introduction, in the range of 20.0-100 µg/L. with a LOD of 9 µg/L. The overall effluent production was 2 mL, corresponding to the consumption of 0.48 µg of 2-metil-3-hydroxy-4-pyridinone, 0.34 mg of NaHCO3, 16 mg of HNO3, 4.4 µg H2O2 and 400µL of sample. Four reference samples were analyzed and a relative deviation<10% was obtained; furthermore, several bathing waters (♯13) were analyzed using the developed method and the results were comparable to those obtained by atomic absorption spectrophotometry (relative deviations<6%).

Micro solid phase spectrophotometry in a sequential injection lab-on-valve platform for cadmium, zinc, and copper determination in freshwaters

“…The idea was to retain the metal ions prior to the determination in an NTA resin column packed in the flow cell, using a reusable SPS approach. The chosen NTA resin is known for its efficiency to retain metals [33,34] and has been effectively used in SPS-SI-LOV approach [35,36]. The idea was to pack the NTA in the flow cell and then send the sample through for the retention of the metal ions (Cd 2þ , Zn 2þ , Cu 2þ ) attaining both matrix elimination and metal ion pre-concentration.…”

Iron speciation in natural waters by sequential injection analysis with a hexadentate 3-hydroxy-4-pyridinone chelator as chromogenic agent

“…Batch studies were performed to evaluate the buffer concentration to attain a final pH E8. A carbonate buffer was chosen, according to previous work by Mesquita et al [3]. Because the buffer capacity is directly dependent on the sample/standard volume (set at pH ¼2) a combined study of the sample/standard volume, using the initial carbonate concentrations, was performed by measuring the pH of the solution after mixing (Supplementary information Fig.…”

“…However, these techniques may require toxic reagents and so alternatives involving low toxic reagents are demanded, in a green chemistry approach. In this context, the use of newly synthesized iron ligands, bidentate 3-hydroxy-4-pyridinone (3,4-HPO) chelators, has been successfully described [2,3]. However, the main drawback reported by the authors was the low solubility of the ligand together with the need of using the ligand in a 3:1 ligand: iron stoichiometry [2], which implies a higher ligand solution volume, as the limited solubility prevents an increase in ligand concentration.…”

A Highly Structured 1,10-Phenanthroline Arrayed Hydrophobic Sulfone Membrane Platform for the Rapid Determination and Speciation of Fe2+/Fe3+ Ions in Water

“…The membrane-based sensor may not be as ultrasensitive as other reported methods, 7,8 as shown in Table 2, but it offers a simple one-step procedure with an easy colorimetric readout. Most of the reported methods are multistep 4 that involve complex methodologies, 2,6 or device fabrication 18,19 that require a high-degree of expertise.…”

“…[4][5][6][7][8][9] Even though most of these technique are highly selective as well as sensitive, but lack of easy operational protocols along with complex methodology limit their usage in field applications. The rapidly growing issues of water pollution make it an ambulatory necessity to design sensing devices that are easy to operate and read by non-technical personnel.…”