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 20.0–100µg/L. with a LOD of 9µg/L. The overall effluent production was 2mL, corresponding to the consumption of 0.48µg of 2-metil-3-hydroxy-4-pyridinone, 0.34mg of NaHCO3, 16mg of HNO3, 4.4µg 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%).