Fluorescent peptide sensor for the selective detection of Cu

A new fluorescent peptidyl chemosensor for Cu²⁺ ions with fluorescence resonance energy transfer (FRET) capabilities has been synthesized via Fmoc solid-phase peptide synthesis. The metal chelating unit, which is flanked by the fluorophores tryptophan (donor) and dansyl chloride (acceptor), consists of the amino acids glycine and aspartic acid (Gly-Gly-Asp-Gly-Gly-Asp-Gly-Gly-Asp-Gly-Gly-Asp-Gly-Gly). Coordination of the Cu²⁺ ions to the metal chelating unit results in fluorescent quenching of both the donor and acceptor fluorophores. Although it was determined that Cu²⁺ binding causes no change in FRET efficiency, emission and Cu²⁺-induced quenching of the acceptor dye can be used to monitor the concentration of the copper ions, with a detection limit of 32 μg L⁻¹. The sensor also demonstrated sensitivity, reversibility and selectivity towards Cu²⁺ in a transition metal matrix at pH 7.0.     

第四周期过渡金属钼磷三元杂多化合物的氧化还原性质研究

研究了Keggin结构钼磷杂多化合物Na₅[PM(H₂O)Mo₁₁O₃₉]·nH₂O(M=Mn²⁺,Co²⁺,Ni²⁺,Cu²⁺,Zn²⁺在溶液中的氧化还原性质,发现环境的改变可对杂多阴离子的极谱半波电位产生影响,其影响程度的大小决定于过渡金属离子本身的性质。取代后的钼磷杂多阴离子的半波电位顺序为Ni²⁺>Co²⁺>Zn²⁺>Cu²⁺>Mn²⁺,pH值的变化影响氧化还原性质,并阐述了变价金属Cu²⁺对杂多阴离子氧化还原性质的影响.     

Remove of Heavy Metals(Cu2+, Pb2+, Zn2+ and Cd2+) in Water Through Modified Diatomite

At present, heavy metal pollution has become a major environmental problem, influencing the survival of human and other creatures. Developing heavy metal ion adsorbents, which are environment friendly, of low cost and good performance is one of the effective means to solve heavy metal pollution. Rich low-grade diatomite mineral, as raw material, was modified with calcium carbonate to improve the adsorption properties of diatomite for heavy metal ions. The effects of dosage(m), pH, adsorbing time(t), temperature(T) and concentration of adsorbent(c) on the removal rate of heavy metal ions(Cu²⁺, Pb²⁺, Zn²⁺ and Cd²⁺) were studied. The results show that under the suitable conditions, T=15 ℃, c=1.5 mmol/L, m=10 g/L, t=60 min, in a weak acid environment, the removal effect of the four kinds of metal ions by modified diatomite is the best.     

UiO-66-NH2/wood的设计构筑及高效去除水中微量重金属离子性能

矿山开采、 金属冶炼、 新型金属材料的发展以及城市供水系统老化所造成的重金属(铅、 镉、 汞、 砷、 铬、 铜及锌等)污染问题已日趋严重. 传统的水处理方法很难有效地去除低浓度的重金属污染物. 本文以天然木材为载体, 采用溶剂热合成法, 在木材三维孔道中原位合成UiO-66-NH₂金属有机框架材料(MOFs)纳米颗粒, 制备了UiO-66-NH₂/wood复合膜材料. 该复合膜材料对去除水中微量重金属离子(Hg²⁺, Cu²⁺)表现出优异的性能. 当处理速率为1.1×10² L?m^-2?h^-1时, 该复合膜材料去除水中微量重金属离子的效率仍可达到90%以上, 且处理后水中重金属离子含量低于国家饮用水标准. 这可归因于木材本身独特的三维孔道结构, 在提高水通量的同时, 还可以增加水溶液中重金属离子与MOFs颗粒的接触机会, 以及孔道内均匀分布的UiO-66-NH₂ MOFs颗粒中的—NH₂可以与重金属离子通过配位作用相结合. 该UiO-66-NH₂/wood复合膜材料还具有良好的重复利用性, 在连续6次循环使用后其去除效率无明显变化, 有望进行实际应用.     

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     

Bioremediation Process and Bioremoval Mechanism of Heavy Metal Ions inAcidic Mine Drainage

Acidic mine drainage(AMD) containing acidity and a broad range of heavy metal ions is classified as hazardous, and must be properly treated. The removal mechanism of heavy metal ions in acidic mine drainage contai- ning Cu²⁺, Fe²⁺, and Zn²⁺ with biological method was studied here. Using 20 mmol/L ethanol as carbon source, Desulfovibrio marrakechensis,one of sulfate reducing bacteria(SRB) species, grew best at 35 ℃ and pH=6.72 with concentrations of 10, 55 and 32 mg/L for Cu²⁺, Fe²⁺ and Zn²⁺, respectively. The removal efficiency for each ion mentioned above was 99.99%, 87.64% and 99.88%, respectively. The mineralogy and surface chemistry of precipitates were studied by means of energy dispersive spectrometer(EDS), X-ray photoelectron spectroscopy(XPS), X-ray diffraction(XRD) combined with control tests. The experimental results demonstrate that the removal mechanism of heavy metal ions by Desulfovibrio marrakechensis is comprehensive function of chemical precipitation, adsorption and bioprecipitation. The biogenic iron sulfide solid was characterized as greigite(Fe₃S₄), while the zinc sulfide solid was characterized as sphalerite(ZnS).     

蒙脱土表面键合配位体固相萃取填料的制备及其对重金属离子的吸附性能

通过酸洗、硅烷偶联剂表面活化、键合苯甲酰异硫氰酸酯对蒙脱土进行改性,制得新型固相萃取(SPE)材料。 采用红外光谱、扫描电子显微镜、X射线光电子能谱表征了改性蒙脱土的结构和形貌。 考察了制备的SPE填料对水中As³⁺、Bi³⁺、Cu²⁺、Sb³⁺、Sn²⁺和Pb²⁺的吸附性能,确定了最佳固相萃取条件,对6种金属离子吸附容量分别为10.83、11.92、12.67、10.43、10.01及10.54 mg/g。 通过SPE与电感耦合等离子体质谱联用测定了样品中As³⁺、Bi³⁺、Cu²⁺、Sb³⁺、Sn²⁺和Pb²⁺ 6种重金属离子的含量,检出限分别为0.024、0.013、0.075、0.037、0.011和0.064 μg/L。     

Adsorption of Heavy Metal Ions from Aqueous Solutions by Zeolite Based on Oil Shale Ash: Kinetic and Equilibrium Studies

Na-A zeolite was successfully synthesized via the alkaline fusion method with oil shale ash as the raw material. The adsorption capacity of it was tested by removing Cu²⁺, Ni²⁺, Pb²⁺ and Cd²⁺ from aqueous solutions. The results reveal the maximum adsorption capacity of adsorbent for Pb²⁺, Cu²⁺, Cd²⁺ and Ni²⁺ were 224.72, 156.74, 118.34 and 53.02 mg/g, respectively. The effects of contact time and pH value of solutions on the adsorption efficiency of the zeolite were evaluated. Besides, The equilibrium adsorption data and the batch kinetic data were correlated with Langmuir and Freundlich models and the pseudo-first-order and pseudo-second-order models separately. The results show that the Langmuir isotherm and the pseudo-second-order equation were more suitable for the adsorption of Na-A zeolite for the metal ions. In addition, Thermodynamic parameters of the adsorption(the Gibbs free energy, entropy, and enthalpy) were also evaluated and discussed. The results demonstrate that the adsorption process was spontaneous and endothermic under natural conditions and the synthesized zeolite was an effective adsorbent for the removal of metal ions from aqueous solution.     

6-(N,N-Dimethylamino)-2-naphthoylacryl Acid: a Highly Selective and Sensitive Fluorescent Sensor of Copper(II)

A novel fluorescent probe, 6-(N,N-dimethylamino)-2-naphthoylacryl acid(ACADAN) was designed and synthesized as a fluorescent sensor for Cu²⁺ in aqueous media. Significant amplification of fluorescence signals without causing any discernible change of maximum fluorescence emission wavelength(λ_max) was observed upon the addition of Cu²⁺. Importantly, ACADAN is capable of recognizing Cu²⁺ selectively in aqueous media in the presence of various biologically relevant metal ions and the prevalent toxic metal ions in the environment with high sensitivity(detection limit was 0.1 μmol/L).     

离子强度对膨润土/木质素磺酸钠接枝丙烯酰胺-马来酸酐复合吸附树脂吸附Pb2+/Cu2+的影响

为揭示外加电解质离子强度对重金属离子吸附的影响规律与内在机制, 制备了膨润土/木质素磺酸钠接枝丙烯酰胺-马来酸酐复合吸附树脂(BLPAMA), 研究了外加电解质离子强度对BLPAMA吸附单一和二元Pb²⁺/Cu²⁺的影响规律, 以及有、无外加0.2 mol/L NaNO₃时BLPAMA对二元Pb²⁺/Cu²⁺的吸附等温线、吸附热力学及吸附动力学。 结果表明, 在单一Pb²⁺或Cu²⁺溶液中, 随离子强度增加, Pb²⁺和Cu²⁺吸附量降低;在二元Pb²⁺/Cu²⁺溶液中, 随离子强度增加, Pb²⁺吸附量降低而Cu²⁺吸附量提高。     

荧光素衍生物水杨醛荧光素腙的合成及对铜(Ⅱ)离子的检测

以荧光素酰肼与5-溴水杨醛反应合成了一种新型荧光素衍生物5-溴水杨醛荧光素腙(BSFH),采用红外、核磁、质谱、元素分析等技术手段对其进行了表征。 通过吸收光谱考察了在水溶液中BSFH对常见金属离子的选择性响应,发现BSFH在可见光区几乎无吸收,当加入常见金属离子时,吸收光谱上除了Cu²⁺之外的其它金属离子在496 nm处出现非常弱的吸收,而当Cu²⁺存在时,可以裸眼看到溶液颜色迅速从无色变为黄色,吸收光谱上在496 nm处出现了相对很强的吸收峰,并且随着Cu²⁺浓度的增加溶液的吸收强度不断增强,说明在水溶液中BSFH对Cu²⁺有很好的选择性。 实验结果表明,该化合物与Cu²⁺的化学计量比为1:1,Cu²⁺浓度线性范围为0.30~10 μmol/L,许多常见的金属离子不干扰Cu²⁺的测定,检测限为0.30 μmol/L,说明在水溶液中BSFH对铜离子具有很高的灵敏度。 据此,BSFH可以简单、快速、灵敏地在水溶液中识别和检测低浓度的铜离子。     

Recycle Adsorption of Cu2+ on Amine-functionalized Mesoporous Silica Monolithic

3-Aminopropyltriethoxysilane functionalized worm-like mesoporous silica monolithic(WMSM-NH₂) was prepared and used as a new regenerable adsorbent for the removal of Cu²⁺ ions. The analysis results show that the WMSM-NH₂ monolithic had a high efficiency value of 99.3% for Cu²⁺ remediation when the Cu²⁺ solution was at an initial concentration of 10.32 mg/L. The regeneration study of the WMSM-NH₂ monolithic presented that the adsorption efficiency of 89.0% was remained and a mass of 92.0% was left after seven adsorption-desorption cycles were executed. The monolithic material with high resistance to the acid and good mechanical stability can facilitate the operations of adsorption and regeneration of the adsorbent.     

A highly selective chemosensor for copper ion based on ICT fluorescence

Simple structural compounds 1 to 3 were synthesized.The presence of Cu²⁺ resulted in the fluorescence and absorption spectra change of 1 and 2,which indicated that 1 and 2 showed a highly selective response to Cu²⁺ over other metal ions.However,3 showed no selectivity for metal ions,which means that the compound could bind with several metal ions,such as,Ni²⁺,Zn²⁺,Cd²⁺.Hg²⁺, Pb²⁺,Fe³⁺,Mg²⁺,Ca²⁺,and Co²⁺,except Cu²⁺ and Ag⁺.The different spectral responses were attributed to the difference in binding sites for 1 and 3.     

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.     

Tuning plasmon absorption of unmodified silver nanoplates for sensitive and selective detection of copper ions by introduction of ascorbate

Silver nanoplates as novel optical sensors for Cu^2＋ detection have been demonstrated.Silver nanoplates are synthesized via previous H_2O_2-NaBH_4 cyclic oxidation-reduction reactions.With introduction of ascorbate as mild reductants,Cu^2＋ ions are reduced into Cu~＋ and the Cu^＋ is further reduced to Cu,which is deposited on the surface of the silver nanoplates.The deposition of the Cu on the surface of the silver nanoplates allows a significant red-shift of their plasmon absorption.Therefore,trace Cu^2＋ can be detected.The shift of the plasmon absorption wavelength of silver nanoplates is proportional to the Cu^2＋concentration over a range of 40-340 μmol L~（-1） with a limit of detection of 9.0 μmol L~（-1）.Moreover,such silver nanoplate-based optical sensors provide good selectivity for Cu^2＋ detection,and most other metal ions do not disturb its detection.Moreover,the practicality of the proposed sensor was tested.This Cu^2＋assay is advantageous in its simplicity,selectivity,and cost-effectiveness.     

改性层状双氢氧化物对铜离子(Ⅱ)和双酚A的协同吸附

采用离子交换法制备了十二烷基苯磺酸根(DBS^-)和柠檬酸根(Cit^3-)复合改性层状双氢氧化物(LDHs),简写为DBS-Cit-LDHs。 利用粉末X射线衍射分析、红外光谱分析、比表面积测定以及元素分析等技术手段对样品进行了表征。 结果表明,DBS^-和Cit^3-已柱撑进入LDHs层间。 研究了DBS-Cit-LDHs对水中重金属离子Cu²⁺和有机污染物双酚A(BPA)的协同吸附性能。 吸附实验结果表明,DBS-Cit-LDHs能同时高效去除Cu²⁺和BPA;对Cu²⁺的强吸附能力缘于DBS-Cit-LDHs层间Cit^3-与Cu²⁺形成了稳定配合物;对BPA的强吸附能力缘于分配作用,且吸附能力与样品比表面积无关。 DBS-Cit-LDHs对Cu²⁺的吸附动力学和热力学分别符合准二级动力学方程和Freundlich等温式;对BPA的吸附分别符合准一级动力学方程和Linear等温式。 二者吸附过程的ΔG^o和ΔH^o均为负值,表明吸附为自发放热过程。     

K~+、Na~+、Ca~(2+)、Mg~(2+)对胜利褐煤平衡复吸水的影响

以胜利褐煤为研究对象,利用FT-IR等手段,用灰分、不同湿度下的平衡复吸水含量等,系统研究了不同相对湿度下K+、Na+、Ca2+、Mg2+的水合作用对胜利褐煤平衡复吸水含量的影响。结果表明,相同浓度不同类型的金属离子与煤样的交换能力的趋势为Ca2+Na+K+Mg2+。金属离子对胜利褐煤平衡复吸水含量影响力的顺序为Mg2+Ca2+Na+≈K+。相对湿度高时,平衡复吸水含量的主要控制因素为游离水分子之间的分子作用力;相对湿度中等时,平衡复吸水含量的主要控制因素为金属水簇与毛细管之间的毛细管作用力;相对湿度低时,平衡复吸水含量的主要控制因素为金属离子的水合作用。     

Highly Sensitive and Selective Chemosensor for Cu2+ Based on a Schiff Base

A new chemosensor based on a Schiff base has been designed and synthesized. Its sensing behavior toward various metal ions was investigated by fluorescence and UV-Vis spectroscopic methods. The fluorescence of the sensor was quenched and the color rapidly changed from canary yellow to brown after the addition of Cu²⁺, while no changes occurred after the addition of other metal ions, which contributes to the detection of Cu²⁺ with naked eyes. The fluorescence quantum yield of the ligand was calculated to be 0.52. The corresponding detection limit of Cu²⁺ was 5.721×10^-7 mol/L, and the 1:1 binding mode of the sensor with Cu²⁺ was revealed by Job's plot.     

Ion-interaction chromatographic studies on metal ions completed with Plasmocorinth B dye

The ion-interaction chromatographic behaviour of Plasmocorinth B (a disulphonated azo dye) and of its complexes formed with metal ions in oxidation states + 2 and + 3 (Cu²⁺ Ni²⁺, Al³⁺, CO³⁺, Fe³⁺, Ga³⁺) was investigated. The effect of cationic ion-pairing agents (tetramethyl-, benzyltrimethyl- and tetrabutylammonium) was also evaluated in the presence of alkali metal ions competitors (Li⁺ and Na⁺). The effects of organic modifier and of pH were also considered. The remarkably different behaviour of the ligand and the complexes suggests the formation of M(II)L⁻ and M(III)L₂²⁻. The stoichiometry of complexes was confirmed by applying the electrostatic theory derived from Gouy-Chapman and a modified Langmuir adsorption isotherm to the experimental data.     

N,N-二甲基吡啶苯甲醛缩对二甲氨基苯甲酰腙的合成及对Cu2+的选择性识别

设计合成了可用于识别铜离子的化合物N,N-二甲基吡啶苯甲醛缩对二甲氨基苯甲酰腙(1), 通过¹H NMR, ¹³C NMR和MS等对其结构进行了表征; 采用荧光光谱和吸收光谱法研究了化合物1与金属离子间的相互作用. 结果表明, 化合物1对Cu²⁺ 呈现良好的选择性, Cu²⁺ 的加入使化合物1的荧光强度增强12.5倍, 加入其它金属离子如Fe³⁺, Zn²⁺, Pb²⁺, Hg²⁺, Cd²⁺, Co²⁺, Ni²⁺, Li⁺, K⁺, Ca²⁺, Mg²⁺ 和 Ag⁺, 仅引起化合物1荧光强度的微降. 采用双倒数线性回归拟合法计算可知, 化合物1与Cu²⁺ 形成了1: 1型强发光配合物, 结合常数为2.0×10⁷ L/mol.