Common Transition Metal Ions Research Articles

A Novel Manganese Ion Delivery Carrier Promotes Immune Cell Proliferation and Enhances Innate Immune Responses.

Manganese is a transition metal that is an essential trace element for human health. Manganese ions (Mn2+), which serve as one of the most common transition metal ions, play vital roles in enhancing innate immune responses. However, immune agonists based on Mn2+ are poorly utilized in clinical trials due to poor chemodynamics and adverse events. In this work, we designed a novel delivery carrier for loading manganese ions by constructing hFn-MT3(Mn2+) protein nanoparticles (termed as NPs(Mn2+)), which contained human ferritin heavy chain (hFn) and metallothionein-3 (MT3), induced by isopropyl β-d-thiogalactoside (IPTG) and manganese ions in the prokaryotic expression system. The NPs(Mn2+) protein nanoparticles could not only stimulate immune cell proliferation but also activate innate immune responses via the cGAS-STING-IRF3 signaling pathway. Collectively, our results unveil a candidate strategy for delivering metal ions beyond Mn2+ and may broaden metal ion clinical use in the field of immunotherapies.

Highly selective fluorescence detection of Pt4+ over Pd2+ and Pt2+ using a polyethyleneimine-based nanosensor prepared via facile three-component reaction

A novel polyethyleneimine (PEI)-based polymeric nanosensor (named PEIMP) was developed for specific fluorescence enhanced sensing of Pt4+ ion in aqueous media. The sensor was fabricated via “one-pot” three-component reaction using ortho-phthalaldehyde (OPA), PEI and mercaptopurine as raw materials, by which the formation of isoindole fluorophore and its chemical grafting onto PEI chain were achieved simultaneously. The morphology, size and structure of PEIMP have been characterized by various techniques. In buffered aqueous solution (pH 7.0), PEIMP had the ability to specifically bind with Pt4+ producing notable increase in fluorescence emission at 463 nm (excited at 395 nm). Based on investigations on the sensing mechanism, the fluorescence turn-on response towards Pt4+ was attributed to the binding of Pt4+ with purine group in PEIMP resulting in the inhibition of photoinduced electron transfer from purine to isoindole fluorophore. Under the optimal conditions (pH 7.0, incubated at 37 ℃ for 20 min) the detection of Pt4+ could be achieved with the linear range of 0.1–10 μM and the detection limit of 80 nM. The sensor had the advantages of low-cost raw materials, simple and environmental-friendly synthesis and analytical detection procedures. What's more, it could selectively and sensitively detect Pt4+ without the effects from common transition metal ions (Pb2+, Fe3+, Cr3+, Al3+, Ag+, Co2+, Hg2+, Cd2+, Cu2+, Mg2+, Ni2+, Mn2+, Zn2+), especially precious metalions of Pt2+ and Pd2+. The proposed method had been successfully applied to quantify Pt4+ in wastewater and urine samples, and also proved to be potential for monitoring Pt4+ in biological systems.

Carbon thick sheet potentiometric sensor for selective determination of silver ions in X-ray photographic film

Innovative screen-printed electrode (SPE) based on Alizarin Red S (ARS) for Ag (I) ion determination was developed. The ionophore content was varied and optimized which indicated that the ink incorporating 30 mg of Alizarin Red S reflects the best experimental performance exhibiting monovalent Nernstian slope value of 59.95 mV decade−1 over a considerable spacious concentration range from 5.0 × 10−7 to 1.0 × 10−2 mol L − 1 with a lower detection limit value of 5.0 × 10−7 mol L − 1. Additionally, the developed sensor stable for more than 112 days without any significant drift in potential exhibited a fast response time (7 s). The interaction between Ag (I) ions and ARS ionophore at the electrode surface was investigated and elucidated using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and FTIR spectra measurement. The proposed sensor achieved constant potentiometric response in pH range of 4–8 and thermally stable to 50 ͦ C. The developed sensor indicates discriminating capability toward Ag (I) ions with regard to most common transition metal ions. The new developed sensor used for determination of Ag (I) ion in x-ray photographic film and can be applied as indicator electrode in precipitation titrations. Furthermore, the method was validated according to IUPAC recommendation parameters.

Separation and Recovery of Scandium from Sulfate Media by Solvent Extraction and Polymer Inclusion Membranes with Amic Acid Extractants.

We report on the separation and recovery of scandium(III) from sulfate solutions using solvent extraction and a membrane transport system utilizing newly synthesized amic acid extractants. Scandium(III) was quantitatively extracted with 50 mmol dm–3N-[N,N-di(2-ethylhexyl)aminocarbonylmethyl]glycine (D2EHAG) or N-[N,N-di(2-ethylhexyl)aminocarbonylmethyl]phenylalanine (D2EHAF) in n-dodecane at pH 2 and easily stripped using a 0.5 mol dm–3 sulfuric acid solution. The extraction mechanisms of scandium(III) extraction with D2EHAG and D2EHAF were examined, and it was established that scandium(III) formed a 1:3 complex with both extractants (HR), that is, Sc(SO4)2–aq + 1.5(HR)2org ⇄ Sc(SO4)R(HR)2org + H+aq + SO42–aq. The equilibrium constants of extraction were evaluated to be 4.87 and 9.99 (mol dm–3)0.5 for D2EHAG and D2EHAF, respectively. D2EHAG and D2EHAF preferentially extracted scandium(III) with a high selectivity compared to common transition metal ions under high acidic conditions (0 < pH ≤ 3). In addition, scandium(III) was quantitatively transported from a feed solution into a 0.5 mol dm–3 sulfuric acid receiving solution through a polymer inclusion membrane (PIM) containing D2EHAF as a carrier. Scandium(III) was completely separated thermodynamically from nickel(II), aluminum(III), cobalt(II), manganese(II), chromium(III), calcium(II), and magnesium(II), and partially separated from iron(III) kinetically using a PIM containing D2EHAF as a carrier. The initial flux value for scandium(III) (J0,Sc = 1.9 × 10–7 mol m–2 s–1) was two times higher than that of iron(III) (J0,Fe = 9.3 × 10–8 mol m–2 s–1).

Effects of Metal Ions on the Aluminum Electrodeposition from Ionic Liquids

In this study, we report on the effects of three common transition metal ions, i.e., Ni2+, Cu2+ and Fe3+ on the electrodeposition of aluminum from a chloroaluminate ionic liquid, evaluated by means of electrochemical and morphological investigation. Aiming at the determination of the morphological and chemical effects on the aluminum coatings, variable amounts of ions were introduced into the electroplating bath. Thick (about 20 μm) Al coatings were obtained by direct deposition (galvanostatic, 10 mA cm2, 2 h) on brass or carbon steel substrates (10 mm diameter disks), and their morphology was examined via rugosimetry, optical and electron microscopy. The chemical composition of the deposits was provided by EDX analysis. Nickel and iron resulted to have only moderate effects on the coatings properties, but copper affected the process even in tiny amounts being detected in the deposits for bath content as low as 10 ppm.

Lanthanum(III) potentiometric sensors based on ethyl benzoyl acetate

Modified carbon paste electrode (CPE) and screen printed electrode (SPE) based on ethyl benzoyl acetate (EBA) were prepared and investigated as lanthanum ion selective electrodes. Effect of various plasticizers (o-NPOE, TCP, DBP, DOS, and DOP) and ionophore content was studied. The reaction mechanism between La(III) and β-diketone ionophore at the electrode surface was studied through scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and IR spectra measurement. The best performance was obtained using modified SPE and CPE electrodes with o-NPOE and TCP plasticizers. These electrodes showed potentiometric response with a Nernstian slope of 21.0, 19.5 and 20.5mV decade−1 over a concentration range from 1.0×10−6 to 1.0×10−2molL−1 with a fast response time of 9, 10 and 13s over the linear concentration range for modified SPE (electrode I; TCP plasticizer) and two modified CPE plasticized with o-NPOE (electrode II) and TCP (electrode III), respectively. The electrodes exhibited constant potentiometric response in pH range 4–8, 5–8 and 4–7 for electrodes I, II and III, respectively. They showed satisfactory good sensitivity toward lanthanum ions with regard to most common transition metal ions. The sensors were applied for determination of La(III) ion in different water samples (tap water and wastewater) with satisfactory and good reproducibility results.

Electrochemical characterization of vanadium(V) sensors modified with 2,4-dinitrophenyl hydrazine. Studying the reaction mechanism using SEM and IR

The determination of vanadium(V) ion in different environmental water samples using rapid, sensitive, and selective potentiometric ion selective electrodes; Screen printed (SPE) and carbon paste (CPE) electrodes modified with 2.4-dinitrophenyl hydrazine (DNPH) was described. Effect of various plasticizers (o-NPOE, TCP, DBP, DOS and DOP) and ionophore content were studied. The best performance was obtained with the electrodes plasticized with o-NPOE or TCP. The electrodes were characterized with scanning electron microscope (SEM) and energy dispersive X ray analysis (EDX) and the mechanism of the electrodes response is discussed based on IR spectra measurement. The sensors exhibit good selectivity toward vanadium(V) ions over a concentration range from 1.0×10−6 to 1.0×10−2molL−1 with a lower detection limit of 1.0×10−6molL−1 and a Nernstian slope of 12, 11 and 10.5mVdecade−1 for SPE (electrode I) and CPEs (electrodes II and III using o-NPOE and TCP plasticizers, respectively). The sensors show response time of 15, 20 and 30s over the linear concentration range for electrodes I, II and III, respectively. The potentiometric response is independent on the pH of the solution in the pH range 5.0–8.0. They display satisfactorily good discrimination toward vanadium(V) ions with regard to most common transition metal ions. The sensors are applied for determination of V(V) ions in different spiked water samples (tap and waste water) with satisfactory results. The method was validated with regard to IUPAC recommendation parameters.

Voltammetric Study and Electrodeposition of Zinc from Room Temperature Ionic Liquid 1-Butyl-1-Methylpyrrolidinium Bis((trifluoromethyl)Sulfonyl)Imide

Voltammetric behavior of Zn(II) introduced into the room temperature ionic liquid 1-butyl-1-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide (RTIL BMP-TFSI) via the addition of ZnCl2 or Zn(TFSI)2 salt was studied. It is surprised that ZnCl2 is highly soluble in this IL because many transition metal chlorides are insoluble in the TFSI-based ILs, leading to the retardation of applying the RTIL BMP-TFSI to electrodeposition. Two redox couples both associated to the redox reaction Zn(II) + 2e− ↔ Zn were observed in the ZnCl2 solution, which resulted from the nonchloride-coordinated and chloride-coordinated Zn(II) species, respectively. However, a single redox couple corresponding to Zn(II) + 2e− ↔ Zn was observed in the Zn(TFSI)2 solution (Figure 1). According to the experiments of voltammetric titration, it was supposed that TFSI anions exhibit much stronger coordinating ability towards Zn2+ ions than to other common transition metal ions, resulting in the high solubility of ZnCl2 in BMP-TFSI. A sufficient amount of chloride anion must be introduced in order to observe the chloride-coordinated Zn(II) species in the Zn(TFSI)2 solution. Afterwards, TFSI anions coordinated to Zn2+ ions were gradually replaced by chloride ions continuously introduced into the Zn(TFSI)2 solution. Finally, no zinc redox couple could be observed once Zn2+ions were completely coordinated with chloride ions. Electrodeposition of Zn was achieved by potentiostatic electrolysis using copper substrates as the electrodes from the IL containing ZnCl2 and Zn(TFSI)2, respectively. Crystalline Zn could be obtained from the two different solutions. The crystallinity and surface morphology of the Zn electrodeposits depended on the applied potentials, and nanostructured Zn could be obtained at some particular electrodepositing potentials. An interesting current-vibration behavior was observed during the potentiostatic electrodeposition of Zn from ZnCl2 solution, and this vibration behavior obviously depended on the applied potentials. It was supposed that the current-vibration behavior was due to a chloride-releasing & chloride-combination mechanism accompanied with the diffusion-drove supplementary of electroactive Zn(II) species because the vibration phenomenon was only observed while the applied potentials were set at where the chloride-coordinated Zn(II) species was reduced in the ZnCl2 solution. Figure 1

Behavior of anions in association with metal ions under hydrometallurgical environments: Part I — OH− effect on various cations

A comprehensive analysis of the effect of OH− on various cations in hydrometallurgical systems has been investigated. Cations chosen for this analysis included groups 1A and 2A, rare-earth elements and other common transition metal ions such as Cu2+, Fe2+, Fe3+, Mn2+, Ni2+, Co2+, Ag+, Cd2+, U4+, UO22+, Hg2+, Al3+ and Zn2+. The Newton-Raphson technique was used to calculate and plot various metal species over a wide range of pH. This study has clearly shown that by adjusting the concentration of OH−, the separation of Fe from Mn, U from V, Ce and Eu from other rare-earth elements, and In from Sn is possible. The effects of hydrated metal ions on the separation and removal of various metals from each other under various conditions is discussed.

Copper-induced fluorescence enhancement and particle-size decrease of a C-6 unsubstituted tetrahydropyrimidine racemate

Fluorescence enhancement and particle-size control of organic fluorophores are of general interest owing to their wide applications. We recently developed a convenient five-component reaction (5CR) for the synthesis of a novel class of racemates, C-6 unsubstituted tetrahydropyrimidines with strong aggregation-induced emission (AIE) properties. The copper-induced fluorescence enhancement and particle-size decrease of the racemate dimethyl 2-(4-hydroxy-3-methoxyphenyl)-1,3-diphenyl-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylate (THP-1), one of the 5CR products, were investigated in this paper. THP-1 shows useful AIE properties, which have attracted great attention recently, and the unusual size-independent emission (SIE) properties reported in our previous work. The fluorescence intensity of THP-1 increased upon adding Cu2+ and a good linear relationship between the fluorescence intensity at the peak position and the Cu2+ concentration was observed in the range of 0–80 μM of Cu2+. The fluorescence response to Cu2+ is highly selective over other common transition metal ions. Most importantly, the suspension particle sizes of THP-1 were found to gradually decrease upon adding Cu2+. This method for controlling organic particle-size is completely different from conventional ones. The investigation results of the influences of Cu2+ on the optical properties and particle sizes of THP-1 in ethanol–water suspensions as well as the molecular stacking mode in the single-crystal of THP-1 indicate that the copper-induced fluorescence enhancement and particle-size decrease are expected to result from the coordination-induced dissociation of intermolecular O–H⋯O bonds connecting non-emissive groups. In addition, THP-1 shows no cytotoxicity in EC109 cells at concentrations below 30 μM. These useful and interesting properties of THP-1 are expected to be very helpful for new probe design, theoretical research on the relationship between intermolecular hydrogen bonds and optical properties, as well as practical applications in organic particle-size control and chemical/biological fluorescence probes.

The Rapid Measurement and Monitoring of Selenite Concentration by Turbidimetry Following its Conversion to Colloidal State by Sulfite Reduction and Acidification

In this study, the rapid reduction of selenious ions using sulfite species at negative pH is described and its use as analytical technique in combination with turbidimetry is proposed. It was found that Se(IV) can be reduced quantitatively at ambient temperature via a combination of sulfite reduction and ultra-acidification with sulfuric acid to a colloidal form that can be determined using turbidimetry. The developed analytical procedure can accurately and reproducibly measure Se(IV) concentrations down to 1 mg/L. For concentrations above 20 mg/L dilution is necessary. Common transition metal ions such as iron(II), copper(II), or zinc(II) up to 10 g/L concentration were found not to have noticeable influence on the precision of the method. Finally the developed technique was shown to be equally effective with real Se(IV)-bearing industrial solutions generated in a zinc concentrate roasting operation, hence making the method particularly useful as a fast and simple process monitoring and control tool.

A highly selective and dual responsive test paper sensor of Hg2+/Cr3+ for naked eye detection in neutral water

A highly selective and sensitive colorimetric and fluorogenic sensor (L1) for Hg2+/Cr3+ is reported. This reagent (L1) was synthesized by reacting 4-((4 (dimethylamino)phenyl)diazenyl)benzene-1-sulfonyl chloride, which has a dimethylaminophenyldiazenyl fragment as a photoactive signalling unit, with 2,2′-(3,3′-azanediylbis(propane-3,1-diyl))diisoindoline-1,3-dione as the receptor fragment. The reagent was characterized by standard analytical and spectroscopic techniques. Electronic spectral studies revealed that the reagent was selective for Hg2+ and Cr3+ in the presence of all other metal ions of Group 1A, IIA and all other common transition metal ions. On binding of L1 to the Hg2+ or Cr3+ centres, a new intense absorption band with a λmax of 509 nm appeared with associated changes in the visually detectable solution colour from yellow to red. Fluorescence spectral studies revealed a significant enhancement in the emission intensities upon coordination to Hg2+ or Cr3+ without any change in the emission wavelength. This could be explained by the efficient interruption of the photo induced electron transfer signalling mechanism involving an unshared pair of electrons from the central tertiary amine centre. An easy to prepare paper test kit, which was obtained by soaking the filter paper in a dichloromethane solution of L1, presents an approach that could be successfully used in the detection of Hg2+ or Cr3+ ions present in neutral aqueous media. This indicates the potential application of this dip strip type sensor for the detection of Hg2+ and Cr3+ in neutral aqueous environments without any spectroscopic instrumentation. Importantly, this reagent binds specifically to Cr3+ in the presence of an excess of iodide ions, which act as a masking agent for Hg2+. To the best of our knowledge, there are very few examples of detection limits lower than the present test strip for Hg2+ in the literature, while, for Cr3+, no such report is available.

Electric Relaxation Processes in Chemodynamics of Aqueous Metal Complexes: From Simple Ligands to Soft Nanoparticulate Complexants

The chemodynamics of metal complexes with nanoparticulate complexants can differ significantly from that for simple ligands. The spatial confinement of charged sites and binding sites to the nanoparticulate body impacts on the time scales of various steps in the overall complex formation process. The greater the charge carried by the nanoparticle, the longer it takes to set up the counterion distribution equilibrium with the medium. A z+ metal ion (z > 1) in a 1:1 background electrolyte will accumulate in the counterionic atmosphere around negatively charged simple ions, as well as within/around the body of a soft nanoparticle with negative structural charge. The rate of accumulation is often governed by diffusion and proceeds until Boltzmann partition equilibrium between the charged entity and the ions in the medium is attained. The electrostatic accumulation proceeds simultaneously with outer-sphere and inner-sphere complex formation. The rate of the eventual inner-sphere complex formation is generally controlled by the rate constant of dehydration of the metal ion, k(w). For common transition metal ions with moderate to fast dehydration rates, e.g., Cu(2+), Pb(2+), and Cd(2+), it is shown that the ionic equilibration with the medium may be the slower step and thus rate-limiting in their overall complexation with nanoparticles.

UV-induced carbonyl generation with formic acid for sensitive determination of nickel by atomic fluorescence spectrometry

UV-induced carbonyl generation with formic acid is used for gaseous sample introduction into an atomic fluorescence spectrometer for the determination of ultra-trace nickel. Compared with conventional carbonyl generation, no toxic gas CO is involved in this work, and volatile Ni(CO) 4 is generated with a single reagent formic acid under the irradiation of UV light (253.7 nm, 15 W). The reaction conditions, including reaction medium, UV irradiation time and reaction temperature, are optimized for the best signal. Under the optimized conditions, a limit of detection of 10 ng L −1 for nickel is obtained without any analyte-pre-concentration, which is comparable to that using in situ trapping technique. Interferences from common transition metal ions, noble metal ions and mineral acids are also investigated. The proposed method is applied to the analysis of three certified reference materials and two organic acid samples for trace nickel, with analytical results in good agreement with certified values or those obtained by electrothermal atomic absorption spectrometry. This is a simple, fairly green and highly sensitive method for ultra-trace nickel determination.

Coated wire silver-ion selective electrode based on a N,N'-bis(2-thienylmethylene)-1,2-diaminobenzene.

A novel membrane coated platinum-wire electrode (MCPWE) based on N,N'-bis(2-thienylmethylene)-1,2-diaminobenzene (BTMD) for highly selective determination of Ag+ ion has been developed. The influences of membrane composition and pH on the potentiometric responses of electrode were investigated. The potentiometric responses are independent of the pH of the test solution in the range of 5.0 - 9.0. The electrode shows a linear response for Ag+ ion over the concentration range of 1.0 x 10(-60 to 1.0 x 10(-1) M with a lower detection limit of 6.0 x 10(-7) M. The electrode possesses a Nernstian slope of 59.7 mV decade(-1) and a fast response time of < or = 17 s and can be used for at least 2 months without any observable deviation. The proposed electrode displayed very good selectivity for Ag+ ion with respect to NH4+ and alkali, alkaline earth and some common transition metal ions. The practical utility of the electrode has been demonstrated by its use as the indicator electrode in the potentiometric titration of an AgNO3 solution with a NaI solution and in determination of the silver content of a developed radiological film.

The kinetic role of metal ions in environmentally relevant redox reactions of chlorite ion and sulfite ion

A brief survey is given about the reactions of chlorite and sulfite ions with some of the most common transition metal ions. The interpretation of the complex kinetic patterns observed in these systems requires the use of comprehensive data treatment and simultaneous evaluation of all experimental results. In most cases, complex formation reactions are in the core of the catalytic redox cycles initiated by the metal ions. The environmental relevance of the kinetic models proposed for catalytic decomposition of chlorite ion and auto-oxidation of sulfite ion is discussed in detail.

Some effects of metal ions on the photogeneration of hydroxyl radicals

The effect of common transition metal ions on the photochemical degradation of a model compound, dequalinium chloride in aqueous solution, irradiated with simulated sunlight at 38 ± 1°C has been investigated. The reactions follow first order kinetics; the addition of a standard volume of hydrogen peroxide markedly enhances the reaction rate constants of these reactions, suggesting that the reactions are hydroxyl radical-mediated in a similar manner to that of the Fenton process. In order to evaluate the contribution of the hydroperoxy radical to photochemical degradation of pharmaceutical formulations as aqueous solutions, the effect of light-generated hydroperoxy radicals was investigated with the same group of metals. The reactions in this case followed second order kinetics and were very much slower than those mediated by hydroxyl radicals; only zinc ions showed a notable increase in the reaction rate constant as compared to that of the control system.

Selective sorption of uranyl and ferric ions on phenolic-type resins of glyoxal-bis-2-hydroxyanil and salicylaldehyde-ethylenediimine

Glyoxal-bis-2-hydroxyanil (GHA) has been reacted with formaldehyde and salicylaldehyde-ethylenediimine (SED) with a mixture of resorcinol and formaldehyde, to prepare the phenolic-type resins Poly(GHA) and Poly(SED), which have high sorption capacities for UO 2 2+ (455 and 334 mg U/g dry weight of resin) and for Fe 3+ (245 and 77 mg Fe/g dry weight of resin). The sorption of UO 2 2+ is maximum in weakly acidic or neutral solutions (pH 6–7), falling rapidly both at lower and higher pH, while the uptake of Fe 3+, sorbed mainly as anionic complexes, is high even in strongly acidic HCl and H 2SO 4 media. Among other common transition metal ions, only Cu(II) has significant sorption on Poly(GHA) and Poly(SED), the saturation capacities being 61 and 31 mg Cu/g dry weight of resin, respectively. Considering the sea water concentrations of transition metal ions as the equilibrium concentrations in the presence of the resin, concentration factors have been calculated for UO 2 2+ (as tricarbonate complex) and common transition metal ions, yielding the highest values for UO 2 2+ with 68 and 39 L sea water/g dry weight of resin on Poly(GHA) and Poly(SED), respectively.