基于荧光内滤效应的锂离子荧光化学传感器研究

报道了一种基于荧光内滤效应的荧光增强型锂离子光化学传感器,将荧光试剂、亲脂性pH指示剂和锂离子中性载体结合在增塑的PVC膜中,Li⁺与H⁺在膜相中的竞争萃取效应引起受亲脂性pH指示剂调制的敏感膜荧光值的变化.推导了有关理论关系式,研究了该传感器的响应特性,并对人工合成样品进行测试,结果较为满意.     

基于荧光内滤效应的锂离子荧光化学传器研究

报道了一种基于荧光内滤效应的荧光增强型锂离子光化学传感器,将荧光试剂、亲脂性pH指标剂和锂离子中性载体结合在增塑的ＰＶＣ膜中,Ｌi^ 与Ｈ^ 在膜相中的竞争萃取效应引起受亲脂性pH指示剂调制的敏感膜荧光值的变化,推导了有关理论关系式,研究了该传感器的响应特性,并对人工合成样品进行测试,结果较了满意。     

基于内滤效应的信号增强型诺氟沙星荧光分析法

基于茜素红和卟啉之间的荧光内滤效应,成功构建了一种分子识别事件与信号报告空间分离的、高选择性的荧光增强型诺氟沙星分析方法。结果表明,无诺氟沙星时,茜素红在420 nm处有最大吸收,这和卟啉的最大激发波长有较大重叠,茜素红和卟啉之间因发生内滤效应导致卟啉的荧光被有效猝灭;而茜素红与诺氟沙星的配合物在523 nm处有最大吸收,和卟啉的最大激发波长不再重叠,即诺氟沙星与茜素红之间的荷移反应破坏了该内滤效应,导致卟啉荧光恢复,据此,可将茜素红的吸收信号转变为高灵敏的卟啉的荧光信号。在最佳实验条件下,诺氟沙星的质量浓度在10 ~ 450 mg?L-1范围内与体系的相对荧光强度(IF/I0F)呈线性关系(r2=0.987 8),检出限(S/N=3)为5 mg?L-1。方法选择性好,常见金属离子和药物辅料不干扰诺氟沙星的测定。该研究利用内滤效应,将灵敏度较低的诺氟沙星紫外可见分析法转换为灵敏度较高的荧光分析法,且无需将分子识别单元和信号转导单元共价连接,无需复杂的荧光探针合成工艺,为设计该类药物的荧光分析法提供了新思路。     

基于荧光内滤效应的荧光增强型钠离子光纤传感器

在吸收型钠离子光化学传感器的敏感膜中加入合适的荧光试剂,应用荧光内滤效应研制成的荧光增强型光纤传感器,在测量灵敏度和抗背景干扰能力方面均有较大的改善,对血清和矿泉水样品中的钠离子含量进行了分析,获得了满意的结果。     

内滤效应设计对非制式爆炸物高锰酸钾检测性能提升策略研究进展

高锰酸钾作为强氧化剂,是重要的非制式爆炸物原料之一,实现对其快速、高灵敏、可视化识别对维护国家公共安全至关重要。近年来,荧光法由于具有选择性好、灵敏度高、响应速度快等优势,通常被用于高锰酸钾检测,其检测原理大多基于内滤效应（IFE）。该文综述了近5年来基于IFE机理检测高锰酸钾的代表性研究成果,总结了IFE机理用于提升高锰酸钾检测性能的设计策略,系统探讨了单发射波长和多发射波长调控,包括配体种类、掺杂元素种类、金属中心个数及种类、不同杂化体系调控对材料光谱性质及高锰酸钾检测性能的影响。展望了该领域基于IFE策略的检测手段可能的发展趋势及应用前景,可为构建高灵敏检测高锰酸钾的IFE体系提供指导。     

基于CdTe量子点内滤效应同步荧光猝灭法测定四环素

以巯基丙酸作为稳定剂制备CdTe量子点,发现CdTe量子点的激发光谱与四环素的吸收光谱有较好重叠,满足发生内滤效应的条件。据此以四环素为吸光体、CdTe量子点为荧光体构建内滤效应荧光传感体系,从而建立一种测定四环素含量的同步荧光猝灭法。实验结果表明,当固定波长差为220 nm时,CdTe量子点的同步荧光最大发射波长为297 nm。在最佳实验条件下,四环素浓度在1.0×10-6~1.0×10-5mol·L-1范围内与体系同步荧光强度呈良好的线性关系,相关系数和检出限分别为0.999和2.5×10-8mol·L-1。该方法灵敏度高、选择性好,应用于牛奶样品中四环素的检测,加标回收率为97.0%~104.3%。     

基于内滤效应的YVO4∶Eu荧光纳米探针测定色氨酸

采用溶剂热法合成了发光性能和水溶性良好的YVO4∶Eu纳米探针(YVO4∶Eu NPs).由于YVO4∶Eu NPs的激发光谱与色氨酸的吸收光谱有很大程度的重叠,二者可发生荧光内滤效应,其中色氨酸为吸光体、YVO4∶Eu NPs为荧光体,YVO4∶Eu NPs的发光被猝灭.基于此,建立了基于YVO4∶Eu NPs内滤效应测定色氨酸含量的方法.对YVO4∶Eu NPs的加入量、反应溶液pH值和反应时间进行了优化,在最佳反应条件下,本方法测定色氨酸的线性范围为4.0×10-6~4.0×10-4 mol/L,检出限为1.0 ×10-6 mol/L(3σ).采用本方法测定了酱油中色氨酸的含量,回收率为95.2%和97.3%.本方法具有简便快速、灵敏准确的特点.     

纳米材料修饰电极在重金属离子检测中的应用

本文介绍了近年来纳米材料修饰电极在重金属离子检测中的研究现状,分析了这些修饰电极的特点,重点阐述了纳米材料在重金属离子检测中的重要作用,列举了一些纳米材料修饰电极在重金属离子检测中的应用,最后对纳米材料修饰电极用于重金属离子的检测研究进行了简要评述和展望。     

A Simple Analytical Method for Monitoring the Total Concentration of Heavy Metal Ions in Environmental Waters

Abstract

A non-sophisticated analytical procedure has been developed for monitoring the sum of heavy metal elements which form stronger EDTA complexes than manganese(II). It is based on complexation of the heavy metals with EDTA and a catalytic indication of its stoichiometry. The equivalence point is determined visually using the substitution reaction between Mn(II)-EDTA and heavy metal ions, followed by the Mn(II)-catalyzed oxidation of Acid Blue 45 dye with hydrogen peroxide. The method has a reasonable accuracy, uses simple test equipment and stable reagents, there are few interferences and it can be carried out by non-technical personnel. Neither preconcentration nor dilution of the sample is required and it is applicable to aqueous samples containing heavy metals down to ppm levels. Some applications to river and groundwaters are shown.     

基于MP-AES的在线检测技术在地表水中重金属监测中的应用

通过集成在线富集和在线热消解技术,建立了基于微波等离子体原子发射光谱法(MP-AES)的地表水中重金属的在线检测技术,对珠江干流之一的西江水样中重金属元素(Cd,Cu,Cr,Ni,Pb,Fe,Mn和Zn)进行现场同时在线监测。结果表明,该在线检测技术对这些重金属元素的定量检测能力满足地表水环境质量标准(GB 3838-2002)的限量要求;据环境标准样品中重金属元素分析结果,测定值与配制标准值一致;自来水加标样品的回收率为81.5%~102%。该检测技术对重金属的检出限为1.14~5.34μg/L,检测结果的相对标准偏差(RSD)为0.79%~9.4%,方法可满足地表水中重金属的现场、快速、连续、准确监测需求。     

Ion-imprinted interpenetrating network gels for solid-phase extraction of heavy metal ions

In the present work, ion-imprinted interpenetrating polymer network (IPN) gels were prepared by free radical/cationic hybrid polymerisation of acrylamide (AAm) and 1,4-butanediol vinyl ether (BVE). These gels were respectively used for separation of Cu²⁺, Ni²⁺ and Zn²⁺ ions in natural water samples. Experimental conditions for effective adsorption of metal ions were optimised with respect to different experimental parameters by column procedures in detail. The optimum pH value for the adsorption of Cu²⁺, Ni²⁺ and Zn²⁺ ions on these sorbents was 6.0. Complete elution of the adsorbed metal ions from the sorbent was carried out using 1.0 mol/L of HCl solution. The optimum sample flow rate and eluent flow rate were, respectively, 1.0 and 0.3 mL/min. Common coexisting ions did not interfere with the separation and determination of the target ions. The accuracy of the proposed method was validated by analysis of the standard reference material (GBW 08301, river sediment). The measured contents of metal ions in the reference material were in good agreement with the certified values. The presented method was successfully applied for the determination of Cu²⁺, Ni²⁺ and Zn²⁺ ions in three different water samples (well water, seawater and waste water).     

明胶-环氧聚醚胺交联膜的合成及其对重金属离子的吸附性能

首先利用聚乙二醇二缩水甘油醚(PEO-DE)、聚二甲基硅氧烷二缩水甘油醚(PDMSDE)与无水哌嗪以1∶1∶1的物质的量之比反应合成环氧封端的聚醚胺(ePEA),然后将ePEA分散在水相中与明胶混合,浇铸固化成膜。利用红外光谱(FT-IR)、X射线衍射(XRD)、示差扫描量热法(DSC)和原子吸收光谱(AAS)等手段研究了明胶-环氧聚醚胺交联膜的结构和离子吸附性能。结果表明,与纯明胶膜相比,交联膜中的环氧聚醚胺与明胶之间出现了新的化学交联结构,在水溶液中的稳定性提高;交联膜对Cu2+、Pb2+、Cd2+均有一定的吸附作用,并且吸附能力随着ePEA含量的增加而增加;吸附过程符合二级动力学模型和Langmuir等温模型。     

A quantitative method for determination of Co(II) based on the inner filter effect of reagents on the Raman scattering signals of water

It is known that Raman scattering signals are one of main interference sources leading up to determination errors in spectrofluorometry, and thus the signals can be easily detected with a common spectrofluorometer. In this contribution, we propose a quantitative method based on the inner filter effect (IFE) of reagents on the Raman scattering signals of solvent by taking the complexation of divalent cobalt ion with 4-[(5-chloro-2-pyridyl)azo]-1,3-diaminobenzene (5-Cl-PADAB) as a model system. By adjusting the excitation wavelength of the spectrofluorometer, we could easily detect the Raman scattering signals of water at 424 nm where the maximum absorption of 5-Cl-PADAB reagent is located. In a solution of 5-Cl-PADAB, the Raman scattering signals of water are decreased owing to the IFE of 5-Cl-PADAB. If Co(II), which could form the binary complex of Co(II)/5-Cl-PADAB and consumes the 5-Cl-PADAB reagent, is present in such a case for a given amount of 5-Cl-PADAB solution, recovered Raman scattering signals could be observed and measured with a spectrofluorometer. It was found that the intensity of the enhanced Raman scattering signals is proportional to the Co(II) concentration over the range from 2.0 × 10⁻⁷ mol L⁻¹ to 1.0 × 10⁻⁵ mol L⁻¹, and the detection limit could reach 1.2 × 10⁻⁷ mol L⁻¹. With that, Co(II) in samples could be detected with R.S.D. values lower than 2.6% and recoveries over the range of 97.2-104.7%.     

PCA-LVQ法及其在RS-FTIR大气环境监测数据处理中的应用

将主成分分析(PCA)用于遥感傅里叶变换红外光谱(Remote Sensing Fourier Transform Infrared:RS-FTIR)的特征提取,结合学习矢量量化(LVQ)神经网络,实现了PCA-LVQ对大气中的8组分混合体系进行快速定性分析的建模方法。并与单纯的LVQ神经网络、反向传播人工神经网络(BP-ANN)得到的结果进行了比较。PCA-LVQ显示出较好的处理数据的能力,它不仅提高了运算速度,而且提高了模型的预测准确度,分类精度达到91.7%。PCA-LVQ的这一预测精度及运算速度,足以满足遥感傅里叶变换红外光谱对大气中有毒气体的实时、在线监测的需要。     

Evaluation of a Collision-Reaction Interface (CRI) for Carbon Effect Correction on Chromium Determination in Environmental Samples by ICP-MS

Spectral interferences in inductively coupled plasma quadrupole mass spectrometry (ICP-MS) may affect several trace element analyses. In this work, the performance of a collision-reaction interface (CRI) for correction of spectral interferences on chromium determination at m/z 52 affected by ⁴⁰Ar¹²C⁺ in a rich-carbon medium was evaluated. Hydrogen or He gases were introduced through sampler or skimmer cones of the CRI for promoting collisions and reactions. Background equivalent concentrations (BEC) and signal-background ratios (SBR) were the chosen parameters for evaluating CRI performance. It was observed that the introduction of both gases through the sampler cone was not effective considering the maximum gas flow rate evaluated at 140 mL min^?1. The best condition to reduce polyatomic interferences caused by carbon containing species was obtained while introducing 60 mL min^?1 of H₂ through the skimmer cone. The trueness of the developed procedure was checked by ⁵²Cr⁺ determination in certified reference materials. Sequential extractions in acetic acid and ammonium acetate (carbon sources) media, according to the Bureau Communautaire de Référence (BCR) of the Commission of the European Communities, was employed for BCR 701 (Lake Sediment) and microwave-assisted digestion was applied for Sewage Sludge from Industrial Origin (BCR 146 R). The feasibility of the CRI to overcome spectral interferences caused by molecular ions containing carbon on ⁵²Cr⁺ determined by ICP-MS was demonstrated.     

1,2-Metallobridging and the Antiperiplanar Effect. Thermodynamic Preference for the Z-Configuration in Imidoyl(Alkali Metals) and their Phosphorus Analogs

We showed that imidoyl- and phosphaethenyl(alkali metals) would thermodynamically prefer the Z-configuration. The bond model analysis of the electronic structures showed that the Z-preference should originate from 1,2-metallobridging by the delocalization of lone pairs on N or P to vacant p-orbitals of the alkali metals and from the antiperiplanar effect of the delocalization from σ _C—M to σ? _{N(P)—R ²} and from n _N(P) to the C—R¹. The Z-preference increases by more electron-withdrawing groups at the carbon atom of the double bond. However, substitution at the nitrogen/phosphorus results in E-preference because of 1,4-chelation of the lone pair of the substituents to alkali metals. Most of halogen derivatives were not stable and eliminate metal halides.