Greener and wide applicability range flow-based spectrophotometric method for iron determination in fresh and marine water

Single flow-based system for the automatic multiparametric nutrients (NPK & Fe) assessment in soil leachates

A multiparametric sequential injection system for the determination of phosphate, nitrite, nitrate, potassium, and iron(III) in a single manifold was developed. The main goal of the proposed method was to develop an efficient tool to assess a number of essential chemical compounds in soils, providing the corresponding information on soil fertility and, additionally, information on possible groundwater contamination. The method was applied for the quantification of the aforementioned parameters in simulated leachates produced in laboratory-scale core columns. The relative standard deviations of ten replicate analyses of a standard were: 6% for phosphate; 2% for nitrite; 2% for nitrate; 5% for potassium; and 6% for iron(III). The limits of detection and quantification were: 2.15 and 7.18 μmol/L for phosphate determination; 0.22 and 0.73 μmol/L for nitrite determination; 3.42 and 8.00 μmol/L for nitrate determination; 39 μmol/L (limit of detection) for potassium determination; and 0.46 and 1.85 μmol/L for iron(III) determination. The sequential injection system was successfully applied for the quantification of multiple soil chemical components (PO43-, NO2-, NO3-, K+, and Fe3+) in soil leachates. The analysis of a sample, involving all the analytes, has a duration of 28 min.

Corrosion process of stainless steel in natural brine as a source of chromium and iron - the need for routine analysis

The corrosion of the installations carrying high salinity water is particularly important in the case of utility and therapeutic waters, such as natural brine. The analysis of such complex systems is challenging in the context of routine analysis of Fe and Cr. Both elements can be determined by UV-Vis spectrophotometry after only 1 : 100 dilution and liquid-liquid extraction (LODFe = 0.03 mg L-1) or thermal chloride stripping (LODCr = 0.02 mg L-1). The corrosion process was characterized. Electrochemically accelerated corrosion showed uneven decomposition of the steel components - Cr is less easily released to the solution than Fe. Iron comprises 53% of the dissolved part, and Cr comprises 8.6%, while the steel originally contained 62% of Fe and 18% of Cr. During the short-term (one week) contact of the brine with stainless steel, the amounts of Fe and Cr released to the brine were insignificant from the perspective of its therapeutic value.

Dual determination of nitrite and iron by a single greener sequential injection spectrophotometric system employing a simple single aqueous extract from Areca catechu Linn. serving as a natural reagent

Dual determination of nitrite and iron was proposed by using a single greener sequential injection (SI) spectrophotometric system employing a simple single aqueous extract from Areca catechu Linn. The extract served as a natural reagent to replace N-(1-naphthyl)ethylenediamine (NED) of the Griess reagent with nitrite and 1,10-phenanthroline with iron. The color products possessed analytical wavelengths at 430 and 560 nm, respectively. Conditions for the SI procedure were optimized using a univariate experimental design. Calibration ranges were up to 5.0 mg L-1 and 10.0 mg L-1 with limits of detection (LODs) of 0.04 mg L-1 and 0.05 mg L-1 for nitrite and iron(iii), respectively, and relative standard deviations (RSDs) being less than 3%. Recoveries of spiked standard nitrite and iron(iii) at 0.3 mg L-1 and 0.5 mg L-1 in water samples were 88 to 104% and 84 to 109%, respectively. The developed method successfully achieved dual determination of nitrite and total iron agreeing at a 95% confidence level with the reference methods of the conventional Griess assay and flame atomic absorption spectrometry (FAAS), respectively. The proposed method utilized locally available material from plants and serves the UN-SDGs.

Hydroxypyridinone-Based Metal Chelators towards Ecotoxicity: Remediation and Biological Mechanisms

Hydroxypyridinones (HPs) are recognized as excellent chemical tools for engineering a diversity of metal chelating agents, with high affinity for hard metal ions, exhibiting a broad range of activities and applications, namely in medical, biological and environmental contexts. They are easily made and functionalizable towards the tuning of their pharmacokinetic properties or the improving of their metal complex thermodynamic stabilities. In this review, an analysis of the recently published works on hydroxypyridinone-based ligands, that have been mostly addressed for environmental applications, namely for remediation of hard metal ion ecotoxicity in living beings and other biological matrices is carried out. In particular, herein the most recent developments in the design of new chelating systems, from bidentate mono-HP to polydentate multi-HP derivatives, with a structural diversity of soluble or solid-supported backbones are outlined. Along with the ligand design, an analysis of the relationship between their structures and activities is presented and discussed, namely associated with the metal affinity and the thermodynamic stability of the corresponding metal complexes.

Sequential injection method for bi-parametric determination of iron and manganese in soil leachates

The aim of this work was to develop a sequential injection (SI) method for the determination of the micronutrients iron and manganese, in soil leachates, as a tool to assess potential groundwater contamination. The described sequential injection method was based on the reaction of iron with chelator MRB12, a greener alternative chromogenic reagent, and the reaction of manganese with zincon, within a single manifold. The developed SI method enabled the determination of iron in the range 0.10-1.00 mg L^-1, and manganese in the range 0.25-2.5 mg L^-1 with a limit of detection of 0.08 mg L^-1 for iron and 0.24 mg L^-1 for manganese. The determination of both parameters was made in 6 minutes, in triplicate. The application to monitor laboratory scale soil core columns (LSSCs), as a simulation of the soil leaching process, proved its efficiency to assess potential contamination of ground waters. Iron and manganese contents were effectively analysed in two different scenarios to mimic the leaching process with rainwater and fertilizer.

Sensitive detection of iron (II) sulfate with a novel reagent using spectrophotometry

In this study, a novel reagent was developed for sensitive detection of iron (II) sulfate, spectrophotometrically. A novel thio-anthraquinone derivative, 1-(Dodecylthio)anthracene-9,10-dione (3), was synthesized from the chemical reaction of 1-Chloroanthraquinone (1) and 1-Dodecanethiol (2) by an original reaction method and was used in the preparation of the novel reagent called Catal's reagent. A synthesized thio-anthraquinone analogue (3) was purified by column chromatography, and its chemical structure was characterized by spectroscopic methods such as Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), and ultraviolet (UV)-visible spectrophotometry. The chemical and molecular structure of the developed thio-antraquinone derivative (3) was illuminated using computational methods with the GaussView5 and Gaussian09 programs. Various solvents including ethanol, methanol, and acetonitrile were examined in the preparation of the reagent. A concentration range from 0.2 mg mL^-1 up to 10 mg mL^-1 of iron (II) sulfate heptahydrate solution in distilled water was prepared. The absorption spectra of Catal's reagent (0.816 mM) showed three peaks between 185 nm-700 nm of wavelength. However, after the reaction with H₂O₂ and the 30 mM trisodium citrate dihydrate mixture in the presence of an iron sulfate (II) solution, a single peak was observed, producing a stable and reddish/brownish homogenous solution (λ max = 304 nm). The following concentrations of iron (II) sulfate heptahydrate was examined using developed protocol and the reagent, and the concentrations were measured spectrophotometrically at 304 nm, 0.2-1 mg mL^-1. Absorbances of reaction mixtures of iron (II) sulfate remained stable up to 48 h. The results indicated that the novel Catal's reagent can be used for sensitive spectrophotometric detection of iron (II) sulfate in aqueous solutions.