Detection Of Metal Cations Research Articles

Metal cation detection based on a stable n-channel accumulation organic electrochemical transistor

An n-channel high-performance, stable OECT device by using a highly crystalline fullerene derivative film as the channel layer has been prepared and has demonstrated promising potential for metal cation detection.

A Review of Dual-Emission Carbon Dots and Their Applications.

Carbon dots (CDs), as a rising star among fluorescent nanomaterials with excellent optical properties and fascinating dual-emission characteristics, have attracted increasing attention in sensing, bio-imaging, drug delivery, and so on. The synthesis of dual-emission CDs (DE-CDs) and the establishment of ratiometric fluorescence sensors can effectively diminish background interference and provide more accurate results than single-emission CDs. Although DE-CDs have generated increased attention in many fields, the review articles about DE-CDs are still insufficient. Therefore, we summarized the latest results and prepared this review. This review first provides an overview of the primary synthesis route and commonly used precursors in DE-CDs synthesis. Then, the photoluminescence mechanism behind the dual-emission phenomenon was discussed. Thirdly, the application of DE-CDs in metal cation detection, food safety analysis, biosensing, cell imaging, and optoelectronic devices has been extensively discussed. Finally, the main challenges and prospects for further development are presented. This review presents the latest research progress of DE-CDs synthesis and its application in ratiometric sensing; hopefully, it can help and encourage researchers to overcome existing challenges and broaden the area of DE-CDs research.

Ferrocene-Based Electrochemical Sensors for Cations

This study investigates novel ferrocene-based electrochemical sensors for metal cation detection via the design, synthesis and characterisation of ferrocene derivatives. Specifically, this research determines the redox potentials of ferrocene versus decamethylferrocene to provide insight into the redox potential variations. The investigation also examines how electrochemical oxidation of the ferrocene moiety can modulate host affinity for transition metal cations via effects such as electrostatic interactions and changes to coordination chemistry. Metal ion coordination to receptors containing functional groups like imine and quinoline is explored to elucidate selectivity mechanisms. These findings advance the fundamental understanding of ferrocene electrochemistry and host–guest interactions, supporting the development of improved cation sensors with optimised recognition properties, sensitivity and selectivity. Overall, this work lays the necessary groundwork for applications in analytical chemistry and sensor technologies via customised ferrocene-derived materials.

Reusable magnetic catalysed synthesis of fluorescent imidazole derivatives: Their use as chromogenic and fluorogenic probes for metal cation's detection

In this contribution, we report the design of magnetic functionalized nanocellulose by an in-Situ approach. The fabricated polymer matrix was utilized as an efficient heterogeneous catalyst for one-pot multi-component synthesis of fluorescent multi-substituted imidazoles under green optimized conditions. The eco-friendly protocol afforded, short reaction times, excellent yields and catalyst easy recycling through magnetic recovery. The geometric optimization, MEP and FMOs have also been carried out at B3LYP‐D3/6–311++G (d, p) level of Density Functional Theory simulations in ethanol to elucidate the substituent's effect on molecule's planarity, surface studies, their electronic structure as well as their intermolecular charge transfer. Furthermore, the synthesized multi-substituted Imidazole derivatives exhibited remarkable fluorescent properties explored in cation metal's chromogenic and fluorogenic detection.

Direct determination of Mn valence states in mixed‐valent manganates by photoluminescence spectroscopy

Mn‐based materials are excellent catalysts with applications in many complex heterogeneous charge transfer processes because of their ability to exist in several stable oxidation states. However, accurate detection of Mn valence states is challenging due to the limitations of X‐ray‐based spectroscopic techniques to successfully resolve individual oxidation states. In this work, we performed a combined photoluminescence (PL) and X‐ray photoelectron spectroscopy (XPS) analysis of many Mn compounds to show that PL spectroscopy can consistently detect Mn in different oxidation states and their composition can be determined through a simple fitting procedure. The results suggest that PL spectroscopy can be a relatively simpler, benchtop alternative to X‐ray based techniques for direct metal cation detection without the need for multiplet fitting analysis.

Two stable cobalt(II) coordination polymers as dual-functional fluorescent sensors for efficient detection of Zn2+/Cu2+ ions and norfloxacin

The detection of metal cations and antibiotics based optical sensing material in the human body and environment is very vital. Two new ternary Co(II) coordination polymers, namely {Co(L)0.5(BTCA)0.5(H2O)]·3H2O}n (1) and [Co(L)(HIPA)·H2O]n (2) (H4BTCA ​= ​1, 2, 3, 4-butanetetracarboxylic acid, H2HIPA ​= ​5-hydroxyisophthalic acid), were constructed and characterized from the rarely reported semi-rigidity 1,4-bis(thiabendazole-1-yl)-2-butene (L) N-donor linker. 1 displays a 2D 3,4-connected 3,4L13 layer, while 2 features a 1D straight chain, and further extends into a 2D supramolecular network via O–H⋯O interactions. 1 and 2 exhibit superior chemical and thermal stability. 1 and 2 can be used as efficient sensors toward Zn2+ ions via turn-on fluorescent enhancing and Cu2+ ions by a turn-off fluorescent quenching effect, separately. They were also applied as probes to detect norfloxacin with high sensitivity, selectivity, and recyclability by fluorescence quenching. The luminescent sensing mechanisms for these analytes were speculated. 1 and 2 are the first dual-functional sensors for the detection of Zn2+/Cu2+ ions and norfloxacin.

ESIPT‐based AIE luminogens: Design strategies, applications, and mechanisms

AbstractIn this review, we present a systematic and comprehensive summary of the recent development and applications of excited‐state intramolecular proton transfer‐based (ESIPT‐based) aggregation‐induced emission luminogens (AIEgens), a type of promising materials that inherit the advantages of ESIPT and AIE, such as large Stokes shift, excellent photostability, and low self‐quenching. We first summarize the backbones that have been used to construct the ESIPT‐based AIEgens and classify the constructed ones based on the relation between ESIPT and AIE unit. According to the sensing mechanisms and design strategies, we have reviewed the applications of ESIPT‐based AIEgens in bioimaging, drug delivery systems, organic light‐emitting diodes, photo‐patterning, liquid crystal, and the detection of metal cations, anions, small molecules, biothiols, biological enzymes, latent fingerprinting, and so on. We have also reviewed the recent advances in the development of new theoretical methods for investigating molecular photochemistry in crystals and their applications in ESIPT‐based AIEgens. We discussed the remaining challenges in this field and the issues that need to be addressed. We anticipate that this review can provide a comprehensive picture of the current condition of research in this field, and promote researchers to make more efforts to develop novel ESIPT‐based AIEgens with new applications.

Nickel contamination analysis at cost-effective silver printed paper-based electrodes based on carbon black dimethylglyoxime ink as electrode modifier

Electrochemical detection of metal cations at paper-based sensors has been suggested as an attractive alternative to current spectroscopic and chromatographic detection techniques due to the ease of fabrication, disposable nature, and low cost. Herein, a novel carbon black (CB), dimethylglyoxime (DMG) ink is designed as an electrode modifier in conjunction with 3-electrode inkjet-printed paper substrates for use in the adsorptive stripping voltammetric electroanalysis of nickel cations in water samples. The developed method provides a novel, low-cost, rapid, and portable adsorptive stripping detection approach towards metal analysis in the absence of the commonly used toxic metallic films. The study demonstrated a novel approach to nickel detection at paper-based sensors and builds on previous work in the field of paper-based metal analysis by limiting the use of toxic metal films. The device sensitivity is improved by increasing the active surface area, electron transfer kinetics, and catalytic effects associated with non-conductive dimethylglyoxime films through CB nanoparticles for the first time and confirmed by electroanalysis. The first use of the CB-DMG ink allows for the selective preconcentration of analyte at the electrode surface without the use of toxic Mercury or Bismuth metallic films. Compared to similarly reported paper-based sensors, improved limits of detection (48 µg L-1), selectivity, and intermetallic interferences were achieved. The method was applied to the detection of nickel in water samples well below World Health Organization (WHO) standards.

Are luminescent Ru2+ chelated complexes selective coordinative sensors for the detection of heavy cations?

The ability of [Ru(bpy)2(bpym)]2+ (bpy = 2,2'-bipyridine; bpym = 2,2'-bipyrimidine) to probe specifically heavy cations has been investigated by means of density functional theory for transition metals, group 12 elements and Pb2+. On the basis of the calculated Gibbs free energies of complexation in water it is shown that all reactions are favorable with negative enthalpies except for Hg2+, with the transition metal cations forming stable bi-metallic complexes by coordination to the bpym ligand. Comparison between the optical and photophysical properties of the Ru2+ probe and those of the coordination compounds does not demonstrate a high selectivity due to very similar characteristics of the absorption and emission spectra. Whereas by complexation the lowest metal-to-ligand-charge-transfer (MLCT) shoulder of [Ru(bpy)2(bpym)]2+ at 462 nm is more or less shifted to the red as a function of the cation, the second MLCT band at 415 nm, less sensitive to the complexation, gains in intensity and is slightly blue-shifted. The visible MLCT emission of [Ru(bpy)2(bpym)]2+ at 706 nm is altered by complexation leading to near IR (800-900 nm) emission in most of the coordination compounds. Complexation to some transition metal cations (Fe, Co, Rh and Pd) generates low-lying metal-centered (MC) excited states that quench luminescence. In contrast to the conclusion of experimental findings by Kumar et al. (Chem. Commun. 2014, 50, 8488-8490), [Ru(bpy)2(bpym)]2+ cannot be proposed as a fast and selective probe for monitoring Pd2+ in aqueous media. Indeed, it does not possess the optical and photophysical characteristics necessary to discriminate Pd2+ ions over a variety of other cations.

Carbon dots-embedded zinc-based metal-organic framework as a dual-emitting platform for metal cation detection

Carbon dots (CDs) was synthesized by hydrothermal method using o-phenylenediamine. The fluorescence property can be used for metal ion sensing, but the solid-state aggregation caused quenching (ACQ) is the troublesome problem to develop the potential applications of carbon dots. Here, the metal-organic framework (MOF) as a host is not only used for restraining the ACQ effect of CDs but also can be constructed by the dual-emitting system ([email protected]). Furthermore, [email protected] with dual-emitting centers can be utilized for detecting copper ions as a ratio fluorescence sensor. The [email protected] fluorescence sensor shows excellent sensitivity, selectivity and strong environmental suitability for sensing Cu2+ ion with the limit of detection (LOD) for Cu2+ ion is 11.712 μM. The [email protected] fluorescent probe was successfully applied to detect Cu2+ ions in an aqueous solution. [email protected] shows a new possibility to fabricate fluorescent molecular probes for the determination of heavy metal ions, which is taken on anti-inference in pH, anion and other influence factors.

Quinoxaline-based chromogenic and fluorogenic chemosensors for the detection of metal cations

The development of molecular and supramolecular optical devices for sensing ionic analytes in solution has emerged as a promissory field in the last decades. In this context, qualitative and quantitative analysis of metal cations based on chromogenic and fluorogenic chemosensors are particularly attractive, especially due to their successfully employment for biological and environmental purposes. In this work, the literature data associated to quinoxaline-based derivatives as chemosensors for metal cations in solution are comprehensively reviewed. Sensing mechanisms, detection limits, solvent effect, work concentration ranges, as well as examples of practical implementation are presented. We believe that the data compilation and pertinent discussion present in this survey should be of interest for researchers of heterocyclic-based chemosensors’ field.

A stable zinc(II)-organic framework as rapid and multi-responsive luminescent sensor for metal ions in water

A very stable ZnII-organic framework, {[Zn(Titpe)0.5(bpodc)]·(H2O)3}n (1, Titpe = 1,1,2,2-tetrakis(4-(imidazol-1-yl)phenyl)ethane, bpodc = benzophenone-4,4-dicarboxylic acid), has been synthesized under hydrothermal conditions. Single-crystal X-ray analysis reveals that 1 crystallizes in the monoclinic system and P21/c space group. Its overall structure is a 3-D stacking with a porosity of 20.95% and a 4-c type topological network; it shows good stability in many solvents. Studies of the solution-phase detection of metal cations show that Fe3+ and Cr3+ ions can quench luminescent emission of 1. Fluorescence titration experiments show that 1 is more selective to Fe3+ (Ksv = 2.8 × 104 M−1) than Cr3+ (Ksv = 1.4 × 103 M−1). The solution-phase detection for anions by 1 also show high selectivity and sensitivity for Cr2O72– anions (Ksv = 1.2 × 104 M−1). With water stability and strong blue luminescence, 1 can potentially apply as a reversible multi-responsive luminescence sensor for Fe3+, Cr3+, and Cr2O72– in aqueous solutions.

Metal Cation Detection in Drinking Water.

Maintaining a clean water supply is of utmost importance for human civilization. Human activities are putting an increasing strain on Earth’s freshwater reserves and on the quality of available water on Earth. To ensure cleanliness and potability of water, sensors are required to monitor various water quality parameters in surface, ground, drinking, process, and waste water. One set of parameters with high importance is the presence of cations. Some cations can play a beneficial role in human biology, and others have detrimental effects. In this review, various lab-based and field-based methods of cation detection are discussed, and the uses of these methods for the monitoring of water are investigated for their selectivity and sensitivity. The cations chosen were barium, cadmium, chromium, copper, hardness (calcium, magnesium), lead, mercury, nickel, silver, uranium, and zinc. The methods investigated range from optical (absorbance/fluorescence) to electrical (potentiometry, voltammetry, chemiresistivity), mechanical (quartz crystal microbalance), and spectrometric (mass spectrometry). Emphasis is placed on recent developments in mobile sensing technologies, including for integration into microfluidics.

Membrane‐Free Detection of Metal Cations with an Organic Electrochemical Transistor

AbstractAlkali‐metal ions, particularly sodium (Na+) and potassium (K+), are the messengers of living cells, governing a cascade of physiological processes through the action of ion channels. Devices that can monitor, in real time, the concentrations of these cations in aqueous media are in demand not only for the study of cellular machinery, but also to detect conditions in the human body that lead to electrolyte imbalance. In this work, conducting polymers are developed that respond rapidly and selectively to varying concentrations of Na+ and K+ in aqueous media. These polymer films, bearing crown‐ether‐functionalized thiophene units specific to either Na+ or K+, generate an electrical output proportional to the cation type and concentration. Using electropolymerization, the ion‐selective polymers are integrated as the gate electrode of an organic electrochemical transistor (OECT). The OECT current changes with respect to the concentration of the ion to which the polymer electrode is selective. Designed as a single, miniaturized chip, the OECT enables the selective detection of the cations within a physiologically relevant range. These electrochemical ion sensors require neither ion‐selective membranes nor a reference electrode to operate and have the potential to surpass existing technologies for the detection of alkali‐metal ions in aqueous media.

Tannic acid capped gold nanoparticles: capping agent chemistry controls the redox activity.

We report the key role of the capping agent in the detection of metal cations using tannic acid (TA) capped gold nanoparticles at both ensembles (using cyclic voltammetry) and with individual particles (using oxidative and reductive nanoimpacts). The results show that the capping agent complexes with Zn2+ and Hg2+ in a reversible and Langmuirian manner in both cases. The sensitivity of detection is determined by the amount of capping agent present on the nanoparticles with similar values seen for both oxidation and reduction reactions. The optimisation of the capping agent loading is therefore key to metal ion detection.

A Selective Fluorescence Sensor for Fe (III) Based on Phenanthroimidazole Imine Compound.

Experimental studies in the aqueous solution are crucial for the detection of metal cations in environmental and biological media. Polymer materials allow to work in aqueous media for fluorescent substances which are insoluble in water. Fluorescence sensor studies of the phenanthroimidazole imine compound (PI) synthesized previously by our group were performed in the polymer medium and the selective response to Fe (III) cation was obtained. The resulting sensor exhibited a selective fluorescence quenching effect to Fe (III). A logarithmic calibration graph was obtained in the range of 5.0 × 10- 5 and 1.0 × 10- 2 M. The interference effects of other ions besides Fe (III) have been examined and it has been observed that PI compound behaves selectively to Fe (III) ion in aqueous media. In addition, regeneration and reproducibility studies were carried out to determine the long-term usage of PI doped polymer film and reproducible results have been obtained for Fe (III) cation.

Multifunctional Luminescence Sensors Assembled with Lanthanide and a Cyclotriveratrylene‐Based Ligand

By using a cyclotriveratrylene‐based ligand 5,12,19‐trimethoxy‐6,13,20‐tricarboxy‐methoxy‐cyclotriveratrylene (H3L), four lanthanide‐based compounds, Eu(L)(DMF)2 (1), Tb(L)(DMF)2 (2), Gd(L)(DMF)2 (3), and Yb(L)(DMF)(H2O) (4), have been constructed. Compounds 1–3 are isostructural and show charming two‐bowl interlocked chains linked by L3– anions and Ln3+ cations. The chains are further linked by C–H···π interactions to form two‐dimensional supramolecular layers, respectively. In 4, L3– anions bridge Yb3+ ions to yield a fascinating three‐dimensional framework. The compounds are characterized by IR and powder X‐ray diffraction. Their solid UV/Vis spectra and fluorescence properties are also studied. By fluorescence detection of metal cations, anions, and organic small molecules, compounds 1 and 2 exhibit high selectivity and sensitivity to Fe3+ ions, MnO4– anions, and nitromethane by quenching processes.

Amino acid derivatized carbon dots with tunable selectivity as logic gates for fluorescent sensing of metal cations

Carbon dots (CDs) modified with ethylene diamine (EDA) and the amino acids (AAs) Cys, His, Lys or Arg were synthesized, and their structures were confirmed by high resolution transmission electron microscopy, Raman spectrometry and X-ray photoelectron spectrometry. It is found that derivatization of the CDs with various AAs systemically modulates their electronic properties, and this results in a tunable selectivity in detection of metal cations via fluorescence quenching. The probes can be performed in aqueous solutions around pH 7. CDs can be excited under 345 nm excitation at room temperature and exhibit fluorescent peak at 450 nm. The decreasing fluorescence intensity is directly proportional to the concentration of metal cations. The limits of detection is 8.8 μg L−1 for Pb(II), 20 μg L−1 for Hg(II), 3.7 μg L−1 for Cu(II), 5.3 μg L−1 for Zn(II), 16 μg L−1 for Fe(III), and 7.2 μg L−1 for Cr(III), respectively. The different fluorescence response of the AA-modified CDs can be converted to logic gates and applied to photoelectronic nanoprobes by using microprocessors. In our perception, this assay has a large potential in terms of high-throughput screening for trace amounts of metal ions.

Luminescent coordination polymers based on a new resorcin[4]arene-functionalized tetracarboxylate: Highly selective luminescent detection of metal cations, anions and small organic molecules

Fluorescence-based probes have received considerable attention because of their superiority in high selectivity and sensitivity. In this work, two novel luminescent isostructural coordination polymers (CPs), namely, [Zn3(HL)2(DMF)2(H2O)2]·2H2O (1) and [Cd3(HL)2(DMF)2(H2O)2]·2H2O (2), were successfully prepared by using a new resorcin[4]arene-based tetracarboxylic acid H4L under solvothermal conditions. In 1 and 2, HL3- anions bridge four metal cations to form charming 2D double layer structures. Drastically, the highly selective and sensitive luminescent detection of small organic molecules, metal cations and anions, particularly of Fe3+, Cr2O72- and nitrobenzene, has been studied using 1 or 2 as a promising luminescent sensor.

Pentiptycene-Derived Fluorescence Turn-Off Polymer Chemosensor for Copper(II) Cation with High Selectivity and Sensitivity.

Fluorescent conjugated polymers (FCPs) have been explored for selective detection of metal cations with ultra-sensitivity in environmental and biological systems. Herein, a new FCP sensor, tmeda-PPpETE (poly[(pentiptycene ethynylene)-alt-(thienylene ethynylene)] with a N,N,N′-trimethylethylenediamino receptor), has been designed and synthesized via Sonogashira cross-coupling reaction with the goal of improving solid state polymer sensor development. The polymer was found to be emissive at λmax ~ 459 nm under UV radiation with a quantum yield of 0.119 at room temperature in THF solution. By incorporating diamino receptors and pentiptycene groups into the poly[(phenylene ethynylene)-(thiophene ethynylene)] (PPETE) backbone, the polymer showed an improved turn-off response towards copper(II) cation, with more than 99% quenching in fluorescence emission. It is capable of discriminating copper(II) cation from sixteen common cations, with a detection limit of 16.5 nM (1.04 ppb).