Method development for the redox speciation analysis of iron by ion chromatography-inductively coupled plasma mass spectrometry and carryover assessment using isotopically labeled analyte analogues

A Fast and Efficient Procedure of Iron Species Determination Based on HPLC with a Short Column and Detection in High Resolution ICP OES

The optimization and application of a new hyphenated procedure for iron ionic speciation, i.e., high performance liquid chromatography (HPLC) with short cation-exchange column (50 mm × 4 mm) coupled to high resolution inductively coupled plasma optical emission spectrometry (ICP hrOES), is presented in this paper. Fe(III) and Fe(II) species were separated on the column with the mobile phase containing pyridine-2,6-dicarboxylic acid (PDCA). The total time of the analysis was approx. 5 min, with a significantly low eluent flow rate (0.5 mL min^-1) compared to the literature. Additionally, a long cation-exchange column (250 mm × 4.0 mm) was used as reference. Depending on the total iron content in the sample, two plasma views were chosen, e.g., an attenuated axial (<2 g kg^-1) and an attenuated radial. The standard addition method was performed for the method's accuracy studies, and the applicability was presented on three types of samples: sediments, soils, and archaeological pottery. This study introduces a fast, efficient, and green method for leachable iron speciation in both geological and pottery samples.

Effect of ultramarathon running on iron metabolism

BACKGROUND

Iron is a vital trace element for energy production and oxygen transportation; importantly, it is essential to athletic performance. Maintaining iron balance is tightly controlled at systemic and cellular levels. This study aimed to determine serum iron tests, hepcidin levels, and cellular iron import and export activities in peripheral blood mononuclear cells (PBMCs) in ultramarathon runners to elucidate the association of systemic inflammation response and iron metabolism.

METHODS

Sixteen amateur runners were enrolled. Blood samples were taken 1 week before, immediately, and 24 h after the run. Plasma hepcidin levels were measured by enzyme-linked immunosorbent assay. The expression levels of divalent metal iron transporter 1 (DMT1), ZRT/IRT-like protein 14 (ZIP14), transferrin receptor 1 (TfR1), and ferroportin (FPN) in PBMCs were measured using real-time quantitative reverse transcription-polymerase chain reaction.

RESULTS

Serum iron concentrations and transferrin saturation significantly decreased immediately after the race and dramatically recovered 24 h post-race. Serum ferritin levels had a statistically significant rise immediately after the race and remained high 24 h after the completion of the race. Ultramarathons were associated with increased plasma interleukin-6 concentrations corresponding to the state of severe systemic inflammation and therefore boosted plasma hepcidin levels. The expression levels of DMT1 and FPN mRNA were markedly decreased immediately and 24 h after the race. The ZIP14 and TfR1 mRNA expression in PBMCs significantly decreased immediately after the race and returned to the baseline level at 24 h post-race. Positive significant correlations were observed between plasma hepcidin and ferritin levels.

CONCLUSION

Iron homeostasis and systemic inflammatory response are closely interconnected. Cellular iron import and export mRNA activities in PBMCs were acutely inhibited during an ultramarathon.

Multi-dentate chelation induces fluorescence enhancement of pyrene moiety for highly selective detection of Fe(III)

Fluorescence enhancement has great advantages and various promising applications for a fluorescent molecular probe, which shows high sensitivity and high selectivity. In this report, a novel pyrene-based fluorescent probe with multidentate ligand (PPD) was synthesized for highly selective detection of Fe(III), which exhibited great fluorescence enhancement response upon the addition of Fe(III) in aqueous solution of pH 3.5 ~ 7.5, with a detection limit of 115 nM. The probe also has good water solubility and photostability. Further fluorescence titration confirmed 1:1 stoichiometric ratio for the probe PPD-Fe(III), which can be applied for quantification of Fe(III). The probe was validated for ferric detection in real water samples by spike and recovery test.

Iron species determination by high performance liquid chromatography with plasma based optical emission detectors: HPLC-MIP OES and HPLC-ICP OES

The paper presents an independent application of two hyphenated techniques, wherein an identical chromatographic system i.e. high performance liquid chromatography (HPLC) was coupled to microwave induced plasma optical emission spectrometry (MIP OES) or inductively coupled plasma optical emission spectrometry (ICP OES). A cation-exchange column and a mobile phase based on pyridine-2,6-dicarboxylic acid (PDCA) were employed to separate Fe(II) and Fe(III) within 300 s. Additionally, two methods of sample preparation were employed. Optimization and validation of both methods were conducted parallel. The applicability was presented with different sample matrix types: post-glacial sediments, archaeological pottery, soils located in the proximity of industry wastes disposal site, river sediments and yerba mate (Ilex paraguariensis). Obtained results were compared in terms of the excitation source (microwave induced or inductively coupled) and supplied gas (nitrogen or argon). The research introduces HPLC-MIP OES for iron speciation analysis and its applicability were critically evaluated with HPLC-ICP OES.

Distinctive detection of Fe2+ and Fe3+ by biosurfactant capped silver nanoparticles via naked eye colorimetric sensing

Distinctive detection of Fe²⁺ and Fe³⁺via naked eye colorimetic sensing.

High-Yield Production of Water-Soluble MoS2 Quantum Dots for Fe3+ Detection and Cell Imaging

Uniform water-soluble MoS2 quantum dots (WS-MSQDs) were synthesized via a sequential combination of sintering/etching/exfoliation method and solvothermal route. The obtained WS-MSQDs with average size of approximately 3.4 nm exhibited sufficient water solubility and remarkable fluorescence properties. The WS-MSQDs were utilized as a probe for detection of Fe3+ ions with high selectivity and specificity. Furthermore, the WS-MSQDs exhibited high fluorescence stability under different conditions. Finally, the WS-MSQDs were successfully applied for the fluorescence imaging of Fe3+ in living cells, which exhibited practical potential for biomedical applications.

Utilizing the interfacial reaction of naphthalenyl thiosemicarbazide-modified carbon dots for the ultrasensitive determination of Fe (III) ions

Since thiosemicarbazide contains numerous nitrogen and sulfur atoms in its structural formula that enhance its strong coordinating abilities with metal ions, it is always selected as the mother molecule for the design of metal-ion sensors. In this report, a thiosemicarbazide derivative (4-naphthalenyl-3-thiosemicarbazide (NTSC)) was synthesized via a single step process and covalently conjugated onto the surfaces of carbon dots (CDs). The modified CDs demonstrated excellent monodispersity, good photostability, and tunable luminescence properties. More importantly, the CDs retained a highly specific Fe³⁺ recognition capacity in contrast to other competing metal ions. Fe³⁺ can efficiently quench the fluorescence of CDs even at fairly low concentration (30μM) with a detection limit as low as 1.68nM. The fluorescence quenching kinetics are likely to involve static quenching, which is caused by specific interactions between NTSC-CDs and Fe³⁺ toward the formation of a ground state complex. Due to their excellent optical performance, low toxicity, and good biocompatibility the NTSC-CDs may be applied to the imaging and monitoring of Fe³⁺ in bacillus subtilis. In effect we successfully fabricated an effective fluorescent nanosensor for both the quantitative detection of Fe³⁺ in aqueous solutions, and its real-time imaging in vivo.

Dual-binding pyridine and rhodamine B conjugate derivatives as fluorescent chemosensors for ferric ions in aqueous media and living cells

Two new pyridine-type rhodamine B chemosensors (RBPO and RBPF) used to detect Fe3+ have been designed and synthesized, and the sensing behavior towards various metal ions was evaluated via UV-vis and fluorescence spectroscopic techniques. Both RBPO and RBPF not only have good spectral responses to Fe3+ in an EtOH/H2O solution (3 : 1, v/v, HEPES, 0.5 mM, pH = 7.33) with low detection limits and high binding constants, but also suffer from less interference from common metal cations. The two chemosensors are further proven to be practical in sensitively monitoring trace Fe3+ in real water specimens. Intracellular imaging applications demonstrated that RBPO and RBPF can be used as two fluorescent chemosensors for the detection of Fe3+ in living human breast adenocarcinoma (MCF-7) cells.

A novel colorimetric and turn-on fluorescent chemosensor for iron(III) ion detection and its application to cellular imaging

A novel rhodamine-based dual probe Rh-2 for trivalent ferric ions (Fe(3+)) was successfully designed and synthesized, which exhibited a highly sensitive and selective recognition towards Fe(3+) with an enhanced fluorescence emission in methanol-water media (v/v=7/3, pH=7.2). The probe Rh-2 could be applied to the determination of Fe(3+) with a linear range covering from 3.0×10(-7) to 1.4×10(-5)M and a detection limit of 1.24×10(-8)M. Meanwhile, the binding ratio of Rh-2 and Fe(3+) was found to be 1:1. Most importantly, the fluorescence and color signal changes of the Rh-2 solution were specific to Fe(3+) over other commonly coexistent metal ions. Moreover, the probe Rh-2 has been used to image Fe(3+) in living cells with satisfying results.