11-Mercaptoundecanoic acid functionalized gold nanoclusters as fluorescent probes for the sensitive detection of Cu2+ and Fe3+ ions

Metal ions are physiologically essential,but excessive metal ions may cause severe risk to plants and animals.Here,we prepared gold nanoclusters(Au NCs) protected by 11-mercaptoundecanoic acid(11-MUA),which have excellent fluorescence properties for the detection of metal ions.The results showed that the copper ions(Cu~(2+)) and iron ions(Fe~(3+)) in the solution have obvious quenching effect on the fluorescence intensity of Au NCs.The detection range of Fe~(3+) was 0.8–4.5 mmol/L(R~2= 0.992) and 4.5–11.0 mmol/L(R~2= 0.997).And Cu~(2+) has a lower linear range(0.1–1.0 mmol/L,R2= 0.993).When EDTA was added into the reaction system,it was observed that the quenching effect of Cu~(2+) and Fe~(3+)on Au NCs showed different phenomenon.Then,the effect of metal ions on the fluorescence of Au NCs was investigated.The selective detection of Cu~(2+) was achieved by EDTA masking of Fe~(3+).In addition,we realized the metal ions detection application of Au NCs in the serum     

The specific detection of Cu(Ⅱ) using an AIE-active alanine ester

Cu(Ⅱ) detection is important because it plays crucial role in several biological processes and ecological systems.Fluorescent techniques have attracted more and more attention in Cu(Ⅱ) detection.In this report,we contribute a novel strategy to use fluorescence spectroscopy for Cu(Ⅱ) specific detection.The specificity relies on the fact that,of the many metal cations,only Cu(Ⅱ) can catalyze the hydrolyzation of a-amino acid ester.The novelty originates from the unique aggregation-induced emission(AIE) property of the fluorescent label.We designed a model a-amino acid ester(TPE-Ala) constructed with alanine and tetraphenylethene-functionalized methanol(TPE-methanol).In comparison with the precursor TPE-Ala, TPE-methanol has lower solubility and is easy to form aggregates in water,thereby displaying a higher fluorescent response.Thus,the Cu(Ⅱ) catalyzed hydrolyzation can be monitored by recording the fluorescence enhancement and fluorescent detection Cu(Ⅱ) is rationally achieved.     

Use of 2-(tert-butoxy)-N-(3-carbamothioylphenyl)acetamide and graphene oxide for separation and preconcentration of Fe(Ⅲ),Ni(Ⅱ),Cu(Ⅱ) and Zn(Ⅱ) ions in different samples

A simple and selective method using a column packed with graphene oxide(GO) as a solid phase extractant has been developed for the multi-element preconcentration of Fe(Ⅲ),Ni(Ⅱ),Cu(Ⅱ) and Zn(Ⅱ)ions prior to flame atomic absorption spectrometric determinations.The method is based on the sorption of mentioned ions on synthesized GO using 2-(tert-butoxy)-N-(3-carbamothioylphenyl)acetamide as a chelating agent.Several parameters on the extraction and complex formation were optimized.Under the optimized conditions(pH 6,flow rate 9 mL/min),metal ions were retained on the column,then quantitatively eluted by HNO3solution(5 mL,3.0 mol/L).The preconcentration factor was calculated as250.The detection limits for the analyte ions of interest were found in the range of 0.11 ng/mL(Ni2+) to0.63 ng/mL(Cu2+).The column packed with GO was adequate for metal ions separation in matrixes containing alkali,alkaline earth,transition and heavy metal ions.     

Construction of CdSe/ZnS quantum dot microarray in a microfluidic chip

Microarray technology has been proved to be greatly helpful for biomedical and biological diagnosis. And the evaluation of its biological applications lies in the detection sensitivity, which requires high intensity and stability of the signal. Recently, several nanomaterials, especially semiconductor nanomaterials, due to their excellent fluorescence properties, have been widely used to construct microarrays for biosensors. Here, we presented an approach for constructing CdSe/ZnS quantum dot (QD) microarray in microfluidic channels on a glass slide by photolithography. The conditions for immobilizing stable and uniform QD microarray on the glass slide were optimized. Several types of QD microarrays with different emission wavelengths and modified groups were constructed using silanization and lithography technology. Based on the fluorescence quenching effect of Cu2+ on QDs, the microfluidic chip with QD microarray was applied for the determination of Cu2+. 1 nmol/L Cu2+ could be detected by this method.     

过渡金属离子识别的1，8-萘二甲酰亚氨衍生物作为荧光传感器的研究

Two fluorosensor systems have been designed and synthesized with their photophysical properties and fluorescence responses toward the transition metal ions studied. The fluorosensor was composed of 1,8-naphthalimide and 4-chloro-1,8-naphthalimide as fluorophore respectively, an amino moiety as the receptor and a hydrocarbon chain as the spacer to link the fluorophore and receptor. Fluorescence intensity of these systems is very weak due to the process of the efficient intramolecular photoinduced electron transfer （PET） in the absence of metal ions. Titration of the transition metal ions can switch on the fluorescence immediately. The intensity of released fluorescence is even higher than the expected from the consideration of the PET in these systems. It may be rationalized that the receptor bound to transition metal ions and the solvation of the fluorophore by the water molecules from the hydrated transition metal salts, may significantly cause fluorescence enhancement.     

Ultra-sensitive detection of uranyl ions with a specially designed high-efficiency SERS-based microfluidic device

The uranyl ion(UO_2~(2+)) poses high risks to human health and the environment, hence its detection and monitoring is of utmost significance. However, the development of an ultra-sensitive, high-efficiency and convenient approach for on-site detection of UO_2~(2+) remains a challenge. Herein, a reliable and reusable surface-enhanced Raman spectroscopy(SERS)-based microfluidic biosensor was developed for rapid detection of UO_2~(2+) in real samples. The detection protocol involved the reaction of 5′-Rhodamine B(RhB)-labeled double-stranded DNA for UO_2~(2+)-specific DNAzyme-cleavage reaction in a U-shaped microchannel. Then, the reaction products were delivered into three parallel samples for high-throughput tests by SERS biochips,where 3 D ZnO-Ag mesoporous nanosheet arrays(MNSs) were modified with a single-stranded DNA(ssDNA). The ssDNAwas sequence-complementary with the 5′-RhB-labeled cleaved-stranded DNA(csDNA) from the reaction products. By the hybridization of ssDNA and csDNA, the signal probe RhB was fixed close to the surface of the ZnO-Ag MNSs to enhance the Raman signal. The limit of detection for UO_2~(2+) with the microfluidic-SERS biosensor was 3.71×10~(-15) M. An over 20,000-fold selectivity towards UO_2~(2+) response was also achieved in the presence of 15 other metal ions. The high-throughput microfluidicSERS biosensor operated well for practical UO_2~(2+) detection, with excellent recoveries in contaminated river and tap water from95.2% to 106.3%(relative standard deviation(RSD) 6.0%, n=6). Although the SERS-based microfluidic biosensor developed in this study was deployed for the detection of UO_2~(2+), the reusable and high-efficiency system may be expanded to the detection of other analytes on-site.     

A novel resorufin based fluorescent “turn-on” probe for the selective detection of hydrazine and application in living cells

In this study, a resorufin derivative RTP-1, which is a novel fluorescent ‘‘turn-on' probe for sensitive detection of hydrazine within 30 min, is designed and synthesized. The selective deprotection of the ester group of the probe by hydrazine led to a prominent enhancement of fluorescent intensity, as well as a remarkable color change from colorless to pink, which could be distinguished by naked eye. The fluorescence enhancement showed decent linear relationship with hydrazine concentration ranging from 0 to 50 mmol/L, with a detection limit of 0.84 mmol/L. The specificity of RTP-1 for hydrazine to a number of metal ions, anions and amines is satisfactory. The sensing mechanism of RTP-1 and hydrazine was evaluated by HPLC, ESI mass spectrometry and density functional theory(DFT).Moreover, we have utilized this fluorescent probe for imaging hydrazine in living cells, and the fluorescence was clearly observed when the cells were incubated with hydrazine(100 mmol/L) for 30 min.     

Quinoline-based colorimetric chemosensor for Cu2+: Cu2+-induced deprotonation leading to color change简

A quinoline-based colorimetric chemosensor(QDB) for Cu2+was synthesized by coupling quinoline-2-carbaldehyde with 4-(dimethylamino)benzohydrazide. Although most transition metal cations can cause redshifts in the UV–vis spectrum of QDB, the response of the chemosensor for Cu2+can be easily distinguished because it exhibits the largest redshift together with a color change from colorless to red in response to Cu2+. Other metal ions have no effect on the specific response of QDB to Cu2+. The significant redshift and color change were attributed to Cu2+-induced deprotonation of NH in the sensor.     

Turn-on fluorescence probe for selective detection of Hg(Ⅱ)by calixpyrrole hydrazide reduced silver nanoparticle: Application to real water sample

A simple and quick method for the synthesis of water dispersible stable silver nanoparticles has been developed. Calix[4]pyrrole octahydrazide(CPOH), has been successfully used as a reducing as well as stabilizing agent for the synthesis of silver nanoparticles. CPOH-AgNps have been duly characterized by SPR, PSA, TEM and EDX-ray. The ability of CPOH-AgNps as selective and sensitive sensor for various ions(Pb(Ⅱ), Cd(Ⅱ), Mn(Ⅱ), Fe(Ⅲ), Ni(Ⅱ), Zn(Ⅱ), Hg(Ⅱ), Co(Ⅱ), Cu(Ⅱ)) by colorimetry and spectrofluorimetry has been explored. CPOH-AgNps were found to be selective only for Hg(Ⅱ) ions. Nanomolar concentration of Hg(Ⅱ) ions can also be determined by spectrofluorimetry by increase in fluorescence intensity. Linear range of detection of Hg(Ⅱ) ions in water was found to be from 1 nmol/L to 1 μmol/L. The method has been successfully applied for determination of Hg(Ⅱ) ions in ground water and industrial effluent waste water samples.     

Optimization of polyacrylonitrile-cysteine resin synthesis and its selective removal of Cu(Ⅱ) in aqueous solutions

Polyacrylonitrile beads(PAN) cysteine(CS) was synthesized from polyacrylonitrile beads(PAN) and cysteine(CS).The content of the functional group and the percentage conversion of the functional group of PAN-CS prepared under the optimum condition using response surface methodology(RSM) for the first attempt were 3.22 mmol/g and 35.78%.The structure was characterized by ET-IR and elemental analysis.The adsorption properties of the resin for Cu(Ⅱ) were investigated by batch and column experiments.Batch adsorption results suggested that PAN-CS had higher adsorption capability for Cu(Ⅱ)than other metal ions and maximum saturated adsorption capacity was 184.7 mg/g.The resin and its metal complexes were studied by FT-IR.Furthermore,the resin can be eluted easily using 1 mol/L HC1.PAN-CS can provide a potential application for selective removal of copper from waste solution.     

Anthrone-spirolactam and quinoline hybrid based sensor for selective fluorescent detection of Fe3+ ions

The synthesis of a novel, and highly selective Fe³⁺ ion sensor based on anthrone-spirolactam and its quinoline hybrid ligand is reported. The designed ligand displayed selective detection of Fe³⁺ ions with enhanced fluorescence emission. The complexation of Fe³⁺ ion led to a red shift of 32 nm from 420 nm to 452 nm, and a several fold increase in intensity with fluorescent green emission. The complexation (detection) of Fe³⁺ ions with ligand resulted in chelation enhanced fluorescence and intramolecular charge transfer through the inhibition of C=N isomerization. This hybrid sensor shows high sensitivity and selectivity, spontaneous response, and works on a wide pH range a minimum detection limit of 6.83 × 10⁻⁸ M. Importantly, the sensor works through the fluorescence turn-on mechanism that overcomes the paramagnetic effect of Fe³⁺ ions. The binding mechanism between the ligand and the Fe³⁺ ions was established from the Job's plot method, optical studies, Fourier transfor infrared spectroscopy, NMR titration, fluorescence life-time studies, and density functional theory optimization. The sensor displayed excellent results in the quantification of Fe³⁺ ions from real water samples. Furthermore, due to its biocompatibility nature, fluorescent spotting of Fe³⁺ ions in live cells revealed its bioimaging applications.     

Binding of some first-row transition metal ions by a poly(iminoethylene)dithiocarbamate copolymer

The binding of the transition metal ions VO²⁺, Fe²⁺, Fe³⁺, CO²⁺, Co³⁺, Ni²⁺ and Cu²⁺ by a poly(iminoethylene) dithiocarbamate copolymer has been investigated by uptake studies and physical measurements (electronic, IR, and ESR spectra and magnetic susceptibility). Metal ions may be bound by both the dithiocarbamato and amino groups of the co-polymer. Binding to nitrogen (in addition to binding to sulphur) increases in the order FE(II)<Ni(II)<Cu(II) and accounted for increasing metal ion uptake by the copolymer in the same order. Factors which determine the relative uptake of the metal ions by the copolymer are discussed.     

Synthesis and characterization of graphene oxide‐based hybrid ligand and its metal complexes: Highly efficient sensor and catalytic properties

A new graphene oxide‐based hybrid material (HL) and its Co(II), Cu(II) and Ni(II) metal complexes were prepared. Firstly, graphene oxide and (3‐aminopropyl)trimethoxysilane were reacted to give graphene oxide–3‐(aminopropyl)trimethoxysilane (GO‐APTMS) hybrid material. After that, hybrid material HL was synthesized from the reaction of GO‐APTMS and 2,6‐diformyl‐4‐methylphenol. Finally, Co(II), Cu(II) and Ni(II) complexes of HL were obtained. All the materials were characterized using various techniques. The chemosensor properties of HL were investigated against Na⁺, K⁺, Cd²⁺, Co²⁺, Cu²⁺, Hg²⁺, Ni²⁺, Zn²⁺, Al³⁺, Cr³⁺, Fe³⁺ and Mn³⁺ ions and it was found that HL has selective chemosensing to Fe³⁺ ion. All the graphene oxide‐supported complexes were used as heterogeneous catalysts in the oxidation of 2‐methylnaphthalene (2MN) to 2‐methyl‐1,4‐naphthoquinone (vitamin K₃, menadione) in the presence of hydrogen peroxide, acetic acid and sulfuric acid. The Cu(II) complex showed good catalytic properties compared to the literature. The selectivity of 2MN to vitamin K₃ was 60.23% with 99.75% conversion using the Cu(II) complex.     

Magnetically recyclable nano copper/chitosan in O‐arylation of phenols with aryl halides

Interaction of chitosan (CS) with Fe₃O₄, followed by embedding Cu nanoparticles (NPs) on the magnetic surface through adsorption of Cu²⁺, and its reduction to Cu^o via NaBH₄, offers a reusable efficient catalyst (Fe₃O₄/CS‐Cu NPs) that is employed in cross‐coupling reactions of aryl halides with phenols, which affords the corresponding diaryl ethers, with good to excellent yields. The catalyst is completely recoverable from the reaction mixture by using an external magnet. It can be reused four times, without significant loss in its catalytic activity.     

Redox behaviors of Fe(II/III) and U(IV/VI) studied in synthetic water and KURT groundwater by potentiometry and spectroscopy

The redox behaviors of Fe(II/III) and U(IV/VI) in both synthetic samples and natural groundwater were investigated with potentiometry, UV/VIS absorption spectroscopy, and time-resolved laser fluorescence spectroscopy. Total dissolved Fe(II/III) concentration along with presence of mixed redox couples of Fe²⁺/Fe³⁺ and Fe²⁺/Fe₂O₃(s) were revealed to be the major factors influencing on the redox potentials. Considerable discrepancies between redox potentials obtained with quantitative analysis and chemical speciation of Fe(II/III) and U(IV/VI) ions were identified in the KAERI Underground Research Tunnel groundwater. Chemical speciation of U(IV) in natural groundwater without considering relevant complexation reaction might cause relatively large uncertainties in redox potential calculations.     

Application of Cloud Point Extraction for Copper,Nickel, Zinc and Iron Ions in Environmental Samples

A cloud point extraction procedure was presented for the preconcentration of copper, nickel, zinc and iron ions in various samples. After complexation by 2‐(6‐(1H‐benzo[d]imidazol‐2‐yl)pyridin‐2‐yl)‐1H‐benzo[d]Imidazole (BIYPYBI), analyte ions are quantitatively extracted in Triton X‐114 following centrifugation. 1.0 mol L^?1 HNO₃ nitric acid in methanol was added to the surfactant‐rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The adopted concentrations for BIYPYBI, Triton X‐114 and HNO₃ and bath temperature, centrifuge rate and time were optimized. Detection limits for Cu²⁺, Fe³⁺, Zn²⁺ and Ni²⁺ ions was 1.4, 2.2, 1.0 and 1.9 ng mL^?1, respectively. The preconcentration factors for all ions was 30, while the enrichment factor of Cu²⁺, Fe³⁺, Zn²⁺ and Ni²⁺ ions was 35, 25, 39 and 30, respectively. The proposed procedure was applied to the analysis of real samples.     

Separation and Recovery of Some Metal Ions Using Pan Sorbed Zinc Silicate as Chelating Ion Exchanger

Abstract

A new inorganic ion exchanger zinc silicate has been synthesized. Its properties such as ion exchange capacity, heat effect and stability etc. have been studied. Sorption of PAN over zinc silicate formed a chelate ion exchanger which showed greater selectivity for some metal ions especially for Cu²⁺, Ni²⁺, Co²⁺, Fe³⁺, Ag⁺, Ag³⁺ and Pt⁴⁺. Selectivity has been determined on the basis of distribution coefficients of these metal ions. Separations of Pt(IV) from Fe(III), Au(III) from Fe(III), Ag(I) from Cu(II) and Au(III) from Cu(II) have been reported. The recovery of Pt(IV) and Au(III) from dilute solutions has also been studied.     

Complexation of 3-hydroxy-2,2′-iminodisuccinic acid (HIDS) with Mg2+, Ca2+, Mn2+, Fe3+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+ ions in aqueous solution

In a search for environmental-friendly metal chelating ligands for industrial applications, the protonation and complex formation equilibria of 3-hydroxy-2,2′-iminodisuccinic acid with Mg²⁺, Ca²⁺, Mn²⁺, Fe³⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ ions in aqueous 0.1 mol L^?1 NaCl solution were studied at 25°C by potentiometric titration. The model for complexation and the stability constants of the different complexes were determined for each metal ion using the computer program SUPERQUAD. In all cases, complex formation was dominated by stable ML ^{n ?4} complexes.     

Silole‐Infiltrated Photonic Crystal Films as Effective Fluorescence Sensor for Fe3+ and Hg2+

We develop a highly effective silole‐infiltrated photonic crystal (PC) film fluorescence sensor with high sensitivity, good selectivity and excellent reproducibility for Fe³⁺ and Hg²⁺ ions. Hexaphenylsilole (HPS) infiltrated PCs show amplified fluorescence due to the slow photon effect of PC because the emission wavelength of HPS is at the blue band edge of the selected PC’s stopband. The fluorescence can be quenched significantly by Fe³⁺/Hg²⁺ ions owing to electron transfer between HPS and metal ions. The amplified fluorescence enhances the sensitivity of detection, with a detection limit of 5 nM for Fe³⁺/Hg²⁺ ions. The sensor is negligibly responsive to other metal ions and can easily be reproduced by rinsing with pure water due to the special surface wettability of PC. As a result, a highly effective Fe³⁺/Hg²⁺ ions sensor based on HPS‐infiltrated PC film has been achieved, which will be important for effective and practical detection of heavy metal ions.     

Ultrasensitive Detection of Cu<Superscript>2+</Superscript> Using a Microcantilever Sensor Modified with L-Cysteine Self-Assembled Monolayer

A microcantilever was modified with a self-assembled monolayer (SAM) of L-cysteine for the sensitively and selectively response to Cu(II) ions in aqueous solution. The microcantilever undergoes bending due to sorption of Cu(II) ions. The interaction of Cu(II) ions with the L-cysteine on the cantilever is diffusion controlled and does not follow a simple Langmuir adsorption model. A concentration of 10^?10 M Cu(II) was detected in a fluid cell using this technology. Other cations, such as Ni²⁺, Zn²⁺, Pb²⁺, Cd²⁺, Ca²⁺, K⁺, and Na⁺, did not respond with a significant deflection, indicating that this L-cysteine-modified cantilever responded selectively and sensitively to Cu(II).