用于多巴胺选择性电化学检测的多孔Fe-N-C纳米颗粒簇

多巴胺(DA)是人类神经系统的神经递质之一,也是诊断多种神经疾病的重要生物标志物,因此,快速准确地检测DA浓度受到广泛关注。本文以普鲁士蓝(PB)为前体制备了一种多孔Fe-N-C纳米颗粒簇,将其修饰在玻碳电极(GCE)表面,发现该修饰电极在使用线性扫描伏安法(LSV)和差分脉冲伏安法(DPV)时能够有效地降低尿酸(UA)和抗坏血酸(AA)的电化学氧化响应,而不影响DA的电化学氧化反应,并能够将三者的氧化峰有效分开,从而可以实现对DA的选择性电化学分析。研究结果表明,在含有高浓度的UA(100μmol/L)和AA(100μmol/L)的DA混合溶液中使用LSV检测DA,分段线性范围可以达到5~100μmol/L和100~700μmol/L,灵敏度分别为8.32×10~(-2)和3.44×10~(-2)A·(mol/L)~(-1),检测下限为5μmol/L。     

基于香豆素的比色探针的合成及对Cu^(2+)的识别EI北大核心CSCD

合成了探针8-(2-肼基苯并噻唑)-4-甲基-7-羟基香豆素(L),通过紫外光谱法研究其识别Cu^(2+)性能,并通过Job’s曲线、红外光谱和质谱研究其对Cu^(2+)的识别机理。结果表明:在二甲基亚砜(DMSO)/水(V∶V=9∶1)溶液体系中,探针溶液中加入Cu^(2+)后,溶液颜色由无色变为浅黄色;探针溶液的紫外可见吸光度与Cu^(2+)浓度在0.125~5μmol/L范围内呈良好的线性关系,线性方程为A=0.037c+0.052,线性相关系数R^(2)=0.9881,检出限为0.02μmol/L,该探针可以定量检测水中的Cu^(2+)。     

Cu-MOF催化过氧化氢应用于多巴胺的检测

本文利用一种具有H_2O_2催化活性的Cu-MOF[Cu_3(BTC)_2(H_2O)_3,简称HKUST-1],构建了以邻苯二胺(OPD)为颜色指示分子的比色传感体系,实现了对H_2O_2和多巴胺(DA)的快速灵敏检测。HKUST-1起到催化H_2O_2氧化OPD的作用,反应体系能够呈现出显著的颜色变化。在优化条件下,415nm处的吸收峰强度与H_2O_2浓度呈双线性关系,线性范围分别为10~50 mmol/L和50~100 mmol/L,相对标准偏差分别为0.9947和0.9995,最低检出限为1.29mmol/L。由于DA能抑制H_2O_2氧化OPD,因此比色传感体系还可以用于快速检测DA,线性范围分别为0.25~5μmol/L和2.5~25μmol/L,相对标准偏差分别为0.9783和0.9705,最低检出限为0.262μmol/L。该项工作拓展了Cu-MOFs材料在生物分子催化和生物传感方面的应用。     

基于三磷酸腺苷-L-半胱氨酸功能化纳米银比色法检测水中痕量Hg~(2+)

基于L-半胱氨酸(L-Cys)和三磷酸腺苷(ATP)功能化的纳米银(AgNPs)建立了一种检测环境水样中Hg~(2+)的比色方法。L-Cys和ATP共同修饰的AgNPs(ATP-L-Cys-AgNPs),在水溶液中分散性良好,经紫外-可见光谱扫描显示在386 nm处有强吸收峰。在pH 9.5条件下,Hg~(2+)可与ATP-L-Cys-AgNPs发生配位反应,导致功能化AgNPs聚集,溶液由亮黄色转变为紫色,在554 nm处出现新的吸收峰,同时伴随着386 nm处吸收值下降。在最佳实验条件下,体系386 nm和554 nm处吸光度比值A_(386nm)/A_(554nm)的变化与Hg~(2+)浓度在1.3×10~(-7)～1.0×10~(-6) mol·L~(-1)范围内成线性关系,线性回归方程为ΔA_(386nm)/A_(554nm)=0.39c(0.1μmol·L~(-1))+0.86,相关系数r=0.9982,检出限为4.0×10~(-8) mol·L~(-1)。该方法简便、快捷、准确,可用于环境水样中Hg~(2+)含量的检测。     

聚乙烯吡咯烷酮保护的纳米银可视化检测三聚氰胺

本文在聚乙烯吡咯烷酮(PVP)保护下制得银纳米粒子(AgNPs),当在pH为8.69的B-R缓冲溶液条件下,向AgNPs溶液中加入三聚氰胺后,AgNPs在392nm波长处的吸光度降低,并在长波处出现新的吸收峰,且AgNPs在392nm处的吸光度降低值(△A)与三聚氰胺的浓度呈现良好的线性关系。基于此,建立了一种灵敏检测三聚氰胺的方法,线性范围为5.0×10~(-8)~2.0×10~(-6) mol/L(相关系数r=0.9951)。三聚氰胺的浓度在0.1×10~(-6)~2.0×10~(-6) mol/L范围,AgNPs溶液的颜色变化可以直接用肉眼分辨,由此可以建立一种三聚氰胺的可视化半定量检测方法。建立的方法能用于合成样品和牛奶中三聚氰胺含量的检测。     

一种新型连续检测镉离子和焦磷酸阴离子的逻辑门荧光传感器及其细胞成像研究

设计并合成了一种基于8-羟基喹啉(8-HQ)的连续检测Cd~(2+)和焦磷酸阴离子(PPi)的荧光传感器L.在传感器L的DMSO/H2O(V/V=1/1,0.01mol/L,Hepes-HClbuffer,pH=7.20)溶液中加入Cd~(2+)后导致荧光发射峰(Em=537 nm)猝灭,检测限低至5.87×10~(-8) mol/L.通过Job's曲线图和质谱验证传感器L和Cd~(2+)离子之间以1∶1化学计量比结合,结合常数为4.38×10~4 L/mol.复合传感器L-Cd~(2+)体系具有通过配体置换法对PPi高度选择性检测性能. L可以作为一种逻辑门荧光传感器检测Cd~(2+)和PPi.传感器L可以用于对活细胞中的Cd~(2+)和PPi的荧光成像.     

一种基于联二萘酚衍生物的荧光探针对铜离子的荧光识别

合成了一种基于联二萘酚结构的荧光探针L并表征了其结构。在CH_3OH/H_2O(HEPES 10 mmol/L,1/1,V/V,pH 7.4)溶液中,探针L对Cu~(2+)表现出高度的选择性识别作用,并具有较强的抗干扰能力。在Cu~(2+)浓度0~50μmol/L范围内,探针L在378 nm处的荧光强度与Cu~(2+)浓度呈现良好的线性关系(R~2=0.9983)。L与Cu~(2+)的结合比为1:1,L对Cu~(2+)的检出限为1.32×10~(-6)mol/L,适用于在近中性及碱性条件下对铜离子的检测。     

橙黄G-Fenton体系催化分光光度法测定雨水中过氧化氢

基于在pH=3.0的H2SO4介质中,利用Fenton体系产生的羟基自由基能够与橙黄G发生反应,使其吸光度降低的原理,建立了一种在常温下测定H2O2浓度的催化光度分析新方法.在橙黄G最大吸收峰478 nm波长处测得的吸光度降低值(△A)与H2O2浓度在0～100 μmol/L范围内呈线性相关,检测限(S/N=3)为0.5μmol/L.该方法简单、方便、快捷,将其应用于雨水中微量H2O2的测定,结果满意.     

基于Ce-BDC的氧化物酶活性检测果汁中抗坏血酸的比色方法研究

以对苯二甲酸(H2BDC)为有机配体,Ce为活性金属中心制备了一种具有氧化物酶活性的金属有机框架材料Ce-BDC,其可以催化无色3,3,5,5-四甲基联苯胺(TMB)生成在652 nm处具有强紫外吸收峰的蓝色氧化反应产物oxTMB。该氧化物模拟酶的催化活性受到pH值和温度的影响,其催化规律遵循米氏反应动力学。抗坏血酸的加入可将oxTMB还原导致溶液蓝色减弱且652 nm处的吸光度下降,该文基于这一现象建立了一种果汁中检测抗坏血酸的比色方法。在优化条件下,抗坏血酸浓度在1.0~30 μmol/L范围内与其652 nm处的吸光度呈良好线性,相关系数为0.991 4,检出限为0.32 μmol/L。方法对实际果汁样品中抗坏血酸的回收率为98.2%~102%,相对标准偏差(RSD)为1.2%~7.2%。该策略可为基于纳米酶的比色方法检测抗坏血酸提供新思路。     

双显色剂双波长分光光度法的研究——Ⅰ.水相中中心离子交换测定微量汞

对Cu(DDTC)_2+Hg~(2+)=Hg(DDTC)_2+Cu~(2+)褪色反应,加入另一种显色剂进行显色反应Cu~(2+)+2BCO=Cu(BCO)_2,在450nm处测量Cu(DDTC)_2吸光度的减少,600nm处测量Cu(BCO)_2吸光度的增加,以两处吸光度差值的和作Hg~(2+)的定量测定,从而建立了测定微量汞的双显色剂双波长分光光度法。该方法的ε=3.7×10~4 L·mol~(-1)·cm~(-1)。检出限为0.14ppm,标准物质检验的相对误差和变异系数分别小于2%和5%。     

Effect of metal ions on enantioseparation of five amino acids by ligand exchange capillary zone electrophoresisEI北大核心CSCD

Enantioseparation of five amino acids was conducted by chiral ligand exchange capillary zone electrophoresis (CLE-CZE). L-His and different metal ions in a certain proportion were used to form chiral recognition complexes. The enantiomers were exchanged with L-His ligands in the complex. Then, the separation of enantiomers was obtained according to the different ligand exchange ability. Effects of the valence and the electron layers of metal ions on the resolution were investigated systemically. Baseline separation of D, L-Phe, D, L-Tyr and D, L-Trp was obtained within 12 min when 4 mmol/L Co(Ⅱ) and 8 mmol/L L-His were added to the phosphate buffer solution (20 mmol/L, pH 8.0). The resolutions of D, L-Phe, D, L-Tyr and D, L-Trp were 1.53, 2.04, and 1.58, respectively. Partial chiral separation of D, L-Ser and D, L-Val was achieved under the same conditions. When Co(II) was used as the central ion, the resolution was better than that of Cu(II) and Zn(II), although they had the same number of electron layers and valence. The resolution of amino acids with Ag(I) as the central ion was not as good as that of divalent metal ions. Metal ions with three electron layers had better separation results than that with four electron layers. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Detection of arsenic and lead in chromite by alkali fusion-acid dissolvingatomic fluorescence spectrometryEI北大核心CSCD

A hydride generation-atomic fluorescence spectrometry （AFS） method was developed for the detection of arsenic （As） and lead （Pb） in chromite by alkali fusing and acid dissolving. The sample was fused by Na2O2 and acidification dissolved by HCl. As was quantified by AFS with 10% （V/V） HCl as the carrier flow agent, and KBH4（15 g/L） as reducing agent. Pb was quantified by AFS with 1% （V/V） HCl as the carrier flow agent, and KBH4（20 g/L）-KOH（10 g/L）-K3［Fe（CN）6］ （15 g/L） as reducing agent. Under the optimum conditions, the correlation coefficient （R2） was 1.0000 in the range of 0.5-10 μg/L, the limit of detection （LOD） was 0.05 μg/g with the relative standard deviations （RSDs） of 1.4%-6.0% and the recoveries of 96.2%-116.7% for As. And the R2 was 0.9998 in the range of 1.25-25 μg/L, the LOD was 0.2 μg/g with the RSDs of 1.5%-3.7% and the recoveries of 95.9%-112.2% for Pb. In addition, the method was validated by certified reference sample analysis and multi-laboratory test, which meets the requirements for the standardized quantitative analysis of trace As and Pb in chromite. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Colorimetric and fluorescence dual-mode detection of arsenic（v） based on cobalt oxyhydroxide nanoplatesEI北大核心CSCD

The oxidase-like activity of cobalt oxyhydroxide （CoOOH） nanosheets is inhibited by arsenic （V） in the system, thereby attenuating the oxidation of p-phenylenediamine （PPD） by CoOOH nanosheets, and changing the absorbance of the solution. Based on this principle, and the fluorescence inner filter effect （IFE） of p-phenylenediamine oxide （oxPPD） on the dye acridine orange （AO）, a colorimetric and fluorescence dualmode method for the quantitative detection of As（V） was established. The variation of absorbance and fluorescence intensity of As（V） with different concentrations was investigated, and the effects of the concentrations of CoOOH nanosheet and PPD, pH of buffer solution, and temperature of reaction were optimized. The results showed that under the optimized conditions, the concentration of As（Ⅴ） had a good linear relationship with the corresponding signal intensity, and the detection limits of colorimetric and fluorescence method were 5 and 10 nmol/L, respectively. The method has been used for the determination of arsenic（V） in lake water located the city center. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Synthesen und Kristallstrukturen neuer chalkogenido‐verbrückter Niob‐Kupfer‐Cluster

Syntheses and Crystal Structures of Novel Chalcogenido‐bridged Niobium Copper Clusters In the presence of tertiary phosphines, the reaction of NbCl₅ and Copper(I) salts with Se(SiMe₃)₂ (E = S, Se) affords the new chalcogenido‐bridged niobium‐copper cluster compounds ( 1 ) and [NbCu₄Se₄Cl (PPh₃)₄] ( 2 ). Using E(R)SiMe₃ (E = S, Se, R = Ph, ⁿPr) instead of the bisilylated selenium species leads to the compounds [NbCu₂(SPh)₆(PMe₃)₂] ( 3 ), [NbCu₂(SPh)₆(PⁿPr₃)₂] ( 4 ), [NbCu₂(SePh)₆(PMe₃)₂] ( 5 ), [NbCu₂(SePh)₆(PⁿPr₃)₂] ( 6 ), [NbCu₂(SePh)₆(PⁱPr₃)₂] ( 7 ), [NbCu₂(SePh)₆(P^tBu₃)₂] ( 8 ), [NbCu₂(SePh)₆(PⁱPr₂Me)₂] ( 9 ), [NbCu₂(SePh)₆(PPhEt₂)₂] ( 10 ), [Nb₂Cu₂(SⁿPr)₈(PⁿPr₃)₂Cl₂] ( 11 ) and [Nb₂Cu₆(SⁿPr)₁₂(PⁱPr₃)₂Cl₄]·2 CH₃CN ( 12 ·2 CH₃CN). By reacting Cu^I salts and NbCl₅ with the monosilylated selenides Se(^tBu)SiMe₃ and Se(ⁱPr)SiMe₃ which have a weak Se–C bond the products [Nb₂Cu₆Se₆(PⁱPr₃)₆Cl₄] ( 13 ), [Nb₂Cu₄Se₂(SeⁱPr)₆(PⁿPr₃)₄Cl₂] ( 14 ) and [Nb₂Cu₆Se₂(SeⁱPr)₁₀(PEt₂Me)₂Cl₂]·DME ( 15 ) are formed which contain selenide as well as alkylselenolate ligands. The molecular structures of all of these new compounds were determined by single crystal X‐ray diffraction measurements.     

Preparation and application of novel polymer nanoparticles in the detection of copper ion and cysteineEI北大核心CSCD

A novel amphiphilic copolymer,dipropenoxystyrene anthracene and acrylic acid copolymer（BASA-AA） was designed and synthesized based on divinyl anthracene. The polymer self-assembled rapidly in water to create polymer nanoparticles（BASA-AA NPs）with a uniform size of 45 nm,no dye leakage,and great brightness（Φ= 36%）. Because of the enormous number of carboxyl groups on the surface of the particles,it can disperse extremely well in water,and can be used for the rapid detection of copper ion and cysteine（Cys）in pure water, with the limit of detection of 45 nmol/L. The fluorescent intensity of the nanoparticles will be greatly reduced after the introduction of copper ion,realizing the detection of copper ion with high selectivity and sensitivity. A composite probe made of BASA-AA NPs and copper ion can detect Cys in the range of 0.1-10 µμmol/L,with the detection limit of 84 nmol/L,due to the high binding capacity of the sulfhydryl group and copper ion. The method is simple and rapid in material synthesis and preparation,and shows high selectivity and sensitivity in pure water. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

基于铜纳米簇检测柠檬黄的方法研究EI北大核心CSCD

采用L-半胱氨酸经一步湿化学法合成了稳定的铜纳米簇(CuCNs),优化了其制备条件,分别运用XPS和FTIR对其性能进行表征。CuCNs的荧光能被柠檬黄(LY)淬灭,推测其机理主要来自内滤效应。基于此,该荧光探针能选择检测LY,线性范围和检出限分别为3.33~60.0μmol/L和1.90μmol/L。该方法用于矿泉水和饮料中LY检测,回收率为95.5%~104.4%。     

An electrochemical aptasensor based on cu2+-induced signal amplification strategy for the detection of ochratoxin aEI北大核心CSCD

A novel electrochemical aptasensor based on a Cu2+-induced signal amplification strategy was constructed for the rapid, sensitive and specific detection of ochratoxin A （OTA）. The OTA aptamer with poly （T） was hybridized with the captured DNA probe on the electrode surface. In the presence of Cu2+ and ascorbic acid, the end of poly（T） was used as a template to in situ grow copper nanoclusters （Cu NCs）. In the absence of targeted OTA, the gold electrodes after decorating Cu NCs were immersed into an acidic environment to release Cu2+. After enriching Cu2+ at a potential of − 1.6 V, the strongest current value of copper was recorded by measuring differential pulse voltammetry （DPV）. In the presence of OTA, the OTA aptamer was tightly bound to the target OTA. The OTA aptamer broke away from the electrode to reduce the growth of Cu NCs, resulting in lower DPV current response. This proposed method was employed to detect OTA with linear range from 0.1 to 50.0 ng/mL, and the detection limit was 41.2 pg/mL. The Cu2+-induced electrochemical aptasensor can be further applied in the analysis of target OTA in coffee solution samples. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Synthesis of a fluorescent probe based on naphthalimide derivative for simultaneous detecting of NO and pH in bioimagingEI北大核心CSCD

A new type of fluorescent probe Na-pHNO was synthesized for the simultaneous detection of NO and pH based on naphthalimide derivative. The probe had good fluorescence property in mixture solution of 99% phosphate buffer solution（PBS）and 1% dimethyl sulfoxide（DMSO）solution. It can produce a yellow-green emission peak at 544 nm,and the fluorescence intensity can be enhanced with the increase of NO concentration or the decrease of pH. The probe Na-pHNO displayed good selectivity,high sensitivity,and strong anti-interference towards NO,exhibiting good fluorescence reversibility at pH 5.5-8.5. The spectral studies showed that the probe Na-pHNO exhibited weak fluorescence due to a dual photoinduced electron transfer（PET）effect. After interacting with NO or pH,the dual PET inhibitory effect occurred,and the fluorescence intensity was significantly enhanced. The fluorescence imaging of probe Na-pHNO in HeLa cells showed that it could realize the visual monitoring of the changes of intracellular pH and NO concentration. The probe has been successfully applied to fluorescence imaging of Caenorhabditis elegans. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

On-line determination of trace-level Cr (VI) by carbon dots-immobilized fluorescent capillary sensorEI北大核心CSCD

A new carbon dots-immobilized fluorescent capillary sensor (CDs-FCAS) was developed by immobilizing CDs on the inner surface of glass capillary through cross-linking with KH550. CDs-FCAS was used for on-line detection of Cr (VI) based on fluorescence quenching reaction between CDs and Cr (VI). After reaction, the sensor was simply cleaned with PBS to recover its fluorescence. Therefore, the reuse of CDs-FCAS was realized. The fluorescence stability of the sensor was good (RSD © 2022, Youke Publishing Co.,Ltd. All rights reserved.