An Optical Sensor Based on Polyvinyl Benzyl Malonate Cross-Linked with Divinyl Benzene Dispersed in a Hydrogel Membrane for Detection of Some Heavy Metals

In previous work we have developed a dicarboxylate functionalized polymer that demonstrated chemical sensing. It showed good response to pH changes as well as to varying concentrations of copper and calcium ions. Our recent in-vest- tigations showed interesting results upon testing the functionalized sensing polymer on heavy metals. This sensor is composed of microspheres of polyvinyl benzyl malonate lightly-cross-linked with divinyl benzene dispersed in a hydrogel membrane. The response of the optical sensor is based on the interaction between the metal cations with the deprotonated functional group. The polymer, thus, undergoes shrinking as a result of neutralization of adjacent negative charges on the back-bone of the polymer. This causes significant changes in the optical properties of the sensing element. The optical changes were measured as absorbance vs. wavelength as the sensing membrane is exposed to solutions of varying concentrations of heavy metal ions. The sensor showed significant increase in absorbance up to a concentration of 5 × 10-3 M to the following metal ions: Ni2+, Zn2+, and Cd2+. Furthermore, the studied capacity of the derivatized microspheres showed close values to Ni2+, Zn2+, Cd2+ (1.20, 1.09, 1.08 mmol/g respectively). These kinds of properly functionalized polymers appear to be suitable, versatile sensing elements for the detection of low concentrations of heavy metal ions. In addition, all of the tested heavy metals showed a similar value of the equilibrium formation constant, (log Kf1 is 2.63). In contrast, the sensor showed no significant response to varying concentrations of K+ and Mg2+ metal ions.

Characterization of the Optical Properties of Heavy Metal Ions Using Surface Plasmon Resonance Technique

The aim of this research is to characterize the optical properties of heavy metal ions (Hg2+, Cu2+, Pb2+ and Zn2+) using surface plasmon resonance (SPR) technique. Glass cover slips, used as substrates were coated with a 50 nm gold film using sputter coater. The measurement was carried out at room temperature using Kretchmann SPR technique. When the air medium outside the gold film is changed to heavy metal ions solution, the resonance angle shifted to the higher value for all samples of heavy metal ions solution. By our developed fitting program (using Matlab software), the experimental SPR curves were fitted to obtain the refractive index of Hg2+, Cu2+, Pb2+ and Zn2+ ions solution with different concentrations. Both the real and imaginary part of refractive index of the heavy metal ions solution increased with the concentration. The results give the basic idea such that the SPR technique could be used as an alternative optical sensor for detecting heavy metal ions in solution.

Optimization of monitoring the stability of surrounding rock in a metal mine

Through analyzing the failure mechanics of rock under blasting effect, the optical fiber sensing system was used to monitor the strain of surrounding rock under blasting effect. Combined with practical exploration, the stability of surrounding rock was computed by numerical simulation using the blasting wave obtained from the site. According to the change regularities of displacement, stress, acceleration, and velocity of tunnels before and after explosion, the layout of key monitoring points was optimized. When disposed the monitoring position of sensors, the regular points should be considered to use as key points and the periodical monitor should be a part of the long-term monitor. In practical application, considering the geology condition in site, monitor points should be added on the area with joints and faults to assure the integrity of monitor data and the preciseness of decision.

Review of Cellulose Nanocrystal-based Fluorophore Materials and Their Application in Metal Ion Detection

Cellulose nanocrystals （CNCs）, a unique and promising natural material extracted from native cellulose, have attracted considerable attention owing to their physical properties and special surface chemistry. This review focuses on chemical conjugation strategies that can be used for preparation of ？uorescent-molecule labeled CNCs and the development of biomaterials. Furthermore, their application in the detection of metal ions and future development prospects are discussed. We hope to provide a clear view of the strategies for surface fluorescent modifcation of CNCs and their application in detection of metal ions.

Cladding Modified Fiber Bragg Grating for Copper Ions Detection

This paper reports a fiber Bragg grating(FBG)as a biosensor.The FBGs were etched using a chemical agent,namely,hydrofluoric acid(HF).This implies the removal of some part of the cladding layer.Consequently,the evanescent field propagating out of the core will be closer to the environ­ment and become more sensitive to the change in the surrounding.The proposed FBG sensor was utilized to detect toxic heavy metal ions aqueous medium namely,copper ions(Cu^(2+)).Two FBG sensors were etched with 20 and 40μm diameters and fabricated.The sensors were studied towards Cu^(2+)with different concentrations using wavelength shift as a result of the interaction between the evanescent field and copper ions.The FBG sensors showed a good response in terms of significant wavelength shift in corresponding to varying Cu2+concentrations when immersed in aqueous mediums.The sensors exhibited excellent repeatability towards Cu ions.The results demonstrate that the smaller FBG etching diameter,the better optical response in terms of wavelength and linearity.

氨基化石墨烯电化学传感器在重金属离子检测中的运用分析

本研究旨在探讨氨基化石墨烯电化学传感器在重金属离子检测中的应用,特别是针对Cd^(2+)和Pb^(2+)的检测。研究内容主要包括氨基化石墨烯(NH_(2)-rGO)、壳聚糖(CS)和聚谷氨酸(Glu)复合材料修饰电极的制备,以及其在电化学检测中的性能评估。通过对不同修饰电极的表征与性能分析,本研究揭示了NH_(2)-rGO/CS/Glu复合材料修饰电极在提高检测灵敏度和选择性方面的显著效果。研究结果表明,相比于裸电极和单一材料修饰电极,NH_(2)-rGO/CS/Glu修饰电极对Cd^(2+)和Pb^(2+)展现出了更高的灵敏度和优异的选择性。此项研究为开发新型高效电化学传感器提供了有价值的参考,对于环境监测和重金属污染控制具有重要意义。

用于检测痕量铅离子的功能化反射结构光纤干涉传感器

铅离子(Pb^(2+))是日常生活中常接触的有毒重金属污染物之一。本研究开发了一种新型反射式光纤干涉传感器,用于检测痕量铅离子。该传感器结构由单模光纤、无芯光纤和细芯光纤(TCF)依次拼接而成。TCF的包层被氢氟酸部分腐蚀并涂覆功能化的水凝胶传感膜。该传感膜选用甲基丙烯酸2-羟基乙酯(2-HEMA)作为识别单体。2-HEMA中的氧原子能与Pb^(2+)发生配体-受体相互作用,形成“-O-Pb-O-”交联结构,从而改变TCF的新包层有效折射率。因此,可以通过观察反射光谱中光信号的变化来检测水溶液中Pb^(2+)的浓度。所提出的传感器具有很高的检测灵敏度(1.926×10^(9)nm·mol^(-1)·L),其检测极限为4.14 ppt(1 ng·L^(-1)=1 ppt),比世界卫生组织(WHO)规定的饮用水中Pb^(2+)(10 ppb,1μg·L^(-1)=1 ppb)浓度低1000倍。此外,利用一个方程组实现了该传感器的温度自校准功能,成功地消除了环境温度的干扰。由于该传感器良好的特异性、稳定性以及反射式结构,非常便于实时远程检测,为环境和人类健康监测提供了广阔的前景。

富咪唑型多孔左旋聚乳酸纳米纤维膜制备及其双重净水性能

为开发具有油水分离和吸附重金属离子双重功能的新型膜材料,利用静电纺丝技术制备左旋聚乳酸(PLLA)纳米纤维膜,再依次采用溶剂诱导结晶和1-(3-氨基丙基)咪唑(API)修饰改性得到富咪唑型多孔PLLA纳米纤维膜,并对其微观形貌、化学基团构成、力学性能和润湿性能进行测试与表征,研究了该纳米纤维膜的油水分离性能和对铜离子的吸附性能。结果表明:当丙酮与水体积比为10∶1、丙酮/水混合溶液用量为0.4 mL/(mg纤维)、处理时间为150 s时,溶剂诱导结晶处理所得PLLA纳米纤维膜中多孔纤维的形貌最佳;API修饰改性并未对多孔纤维的形貌和直径产生过多影响,改性后PLLA纳米纤维膜表面出现的咪唑和酰胺基团能够有效改善其润湿性能,使静态水接触角下降了15.6°;与未改性PLLA纳米纤维膜相比,所制得富咪唑型多孔PLLA纳米纤维膜的脆性有所增加,但其断裂强度仍能达到未改性的PLLA纳米纤维膜断裂强度的96.6%,整体力学性能保持良好;利用该纳米纤维膜可实现有效油水分离,分离通量为1044.9 L/(m^(2)·h),分离效率可达99.1%,且其对铜离子吸附性能良好,在pH值为6的铜离子溶液中接触24 h后,对铜离子吸附量可达41.46 mg/g。

基于Fe_(3)O_(4)-MoS_(2)-全氟磺酸纳米复合材料的铅离子电化学传感器

采用Fe_(3)O_(4)-MoS_(2)-全氟磺酸复合材料修饰玻碳电极(GCE),基于电化学传感原理,使用阳极方波伏安法检测水中微量的铅离子。通过扫描电子显微镜(SEM)、能量色散X射线光谱仪(EDS)、Raman光谱分析仪和X射线光电子能谱仪(XPS)进行物理表征。结果表明Fe_(3)O_(4)已较均匀地分布在MoS_(2)上。为了得到良好的实验效果,优化醋酸盐(Hac-NaAc)缓冲溶液的pH值为3.6,最佳沉积时间为120 s,最佳沉积电位为-0.6 V,在滴加5μL的Fe_(3)O_(4)-MoS_(2)和5μL的全氟磺酸条件下进行测试,实验结果表明在0.1~0.6μmol·L^(-1)铅离子浓度范围,Fe_(3)O_(4)-MoS_(2)-全氟磺酸-GCE传感器的线性度良好,灵敏度和检测限分别为25.05μA/(μmol·L^(-1))和0.11μmol·L^(-1)。该检测方法快速便捷,具有低成本、高效率和易操作的特点。

Progress on sensors based on nanomaterials for rapid detection of heavy metal ions

The heavy metal ions,especially Cd^(2+),Pb^(2+) and Hg^(2+),show extremely hazard to the environment and human being.The measurement of heavy metal ions using sensors is catching more and more attention for its advantages of high sensitivity and selectivity,low-cost,convenience to handle and rapid detection.In recent years,nanomaterials such as gold nanoparticles(NPs),magnetic nanoparticles,graphene and nanocomposite materials are applied in sensors for improving sensitivity and selectivity,making the research on electrochemical(EC) sensors,spectrometric biosensors and colorimetric biosensors become a hot spot in the application to investigate heavy metal ions,in particular,Cd^(2+),Pb^(2+) and Hg^(2+).In this short review,the research of advanced detection of Cd^(2+),Pb^(2+) and Hg^(2+) and its progress based on nanomaterial sensors in recent years is reviewed.

Electroless silver plating for metallization of near-field optical fiber probes

By using mercaptopropyltrimethoxysilane （MPTS） self-assembled monolayers （SAMs）, electroless silver plating is developed for the metallization of near-field optical fiber probes. This method has the advantages of controllability, no pinholes, convenience, low cost, and smooth tip surface. The metallized probes are characterized by optical microscopy, scanning electron microscopy （SEM）, and energy dispersive X-ray spectroscopy （EDXS）.

Fast removal of heavy metal ions and phytic acids from water using new modified chelating fiber

The graft copolymerization of acrylic acid（AA） onto polyethylene glycol terephthalate（PET） fiber initialed by benzoy peroxide （BPO） was carried out in heterogeneous media.Moreover,modification of the grafted PET fiber（PET-AA） was done by changing the carboxyl group into acylamino group through the reaction with dimethylamine.The modified chelating fiber（NDWJN1） was characterized using elementary analysis,SEM and FT-IR spectroscopy.Adsorption kinetic curves indicated that NDWJNl could fast remove heavy metal ions and phytic acids from water effectively.Furthermore,batch kinetic studies indicated that heavy metal ions adsorbed to NDWJNl could be filted well by both pseudo-first-order and pseudo-second-order adsorption equations,but the intra-particle diffusion played a dominant role in the adsorption of phytic acids.

磷酸盐对纳米二氧化钛吸附水体中重金属离子行为的影响和机理分析

纳米二氧化钛(n TiO_(2))被广泛应用于去除水体中的重金属。磷酸盐作为水体中普遍存在的无机阴离子,能够对重金属离子在n TiO_(2)上的吸附特征产生影响。本文聚焦磷酸盐存在条件下n TiO_(2)胶体颗粒对典型重金属离子(Zn^(2+)和Cd^(2+))的吸附行为,以电感耦合等离子体发射光谱法(ICP-OES)测定吸附平衡后水相中重金属离子的浓度。通过批量吸附实验考察不同水化学条件下(离子强度和共存阴离子),磷酸盐对n TiO_(2)胶体颗粒吸附水体中Zn^(2+)和Cd^(2+)特征的影响规律。采用经典吸附等温线模型对实验数据进行拟合,并结合纳米颗粒的Zeta电位和粒径变化等表征手段揭示了相关吸附机制。研究发现:①磷酸盐的存在能有效地增强重金属在n TiO_(2)上的吸附,Zn^(2+)和Cd^(2+)的最大吸附量分别由121.1mg/g和84.7mg/g增加至588.3mg/g和434.8mg/g,增加了3.8~4.1倍。这主要由于磷酸盐能够通过桥连作用形成金属-磷酸盐-n TiO_(2)三元络合物以及增加重金属离子和胶体颗粒之间的静电引力,从而增强n TiO_(2)对重金属离子的吸附。②背景溶液中离子强度的增加会降低n TiO_(2)对重金属离子的吸附效果。当背景溶液中离子强度(NaCl浓度)从0增加至10mmol/L时,n TiO_(2)与金属离子之间的静电吸引会减弱,同时Na+与重金属离子竞争n TiO_(2)表面吸附位点亦降低了n TiO_(2)对重金属离子的吸附。③共存竞争性阴离子(如Cl-、NO_(3)^(-)和SO_(4)^(2-))会削弱磷酸盐对n TiO_(2)吸附金属离子的增强作用,抑制顺序为:SO_(4)^(2-)>NO_(3)^(-)>Cl-,即与其离子半径的数量级成反比。这是由于共存阴离子与磷酸盐竞争n TiO_(2)表面的吸附位点所致。研究结果表明,磷酸盐可以显著地增强n TiO_(2)对重金属离子的去除效能,但是去除效能的大小会受到背景溶液中水化学条件的影响。

基于丝网印刷传感器的重金属现场快速检测仪研制

基于丝网印刷传感技术研制的现场快速重金属检测仪,采用微分电位溶出的原理,可应用于水样、污泥、食品、农产品中重金属铅的快速检测.该仪器具有体积小、便于携带、检测速度快、灵敏度高、操作简便且耗样量少等优点.对某地污泥中的铅进行含量测定,结果显示,测定结果的相对标准偏差RSD小于2%,回收率为98.49%~101.58%,具有良好的准确度和精密度.经过样品前处理后,单个样品检测时间约3 min.该仪器在现场痕量重金属检测方面具有良好的应用前景.

辐射接枝法制备氧肟化超高分子量聚乙烯及其重金属吸附性能

采用60Co-γ预辐射接枝法将丙烯酸和丙烯酰胺先后接枝于超高分子量聚乙烯纤维上,随后用羟胺碱溶液对纤维进行氧肟化改性,制备出含氧肟酸基、酰胺基和羧基的超高分子量聚乙烯纤维吸附剂。扫描电子显微镜(SEM)图、傅里叶变换衰减全反射红外光谱(ATR-FTIR)谱图和热重曲线均表明,丙烯酰胺和丙烯酸成功接枝到纤维上,且氧肟化反应成功将酰胺基转化为氧肟基。重金属离子吸附性能测试结果表明:所制备的超高分子量纤维吸附剂对Cu(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ) 3种重金属离子吸附容量最高可达到318 mg/g、165 mg/g、140 mg/g(吸附质量浓度为500 mg/L,时间为4 h);在竞争吸附实验中,对Cu(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)离子的去除率分别为99.5%、43.5%、60.5%(Cu(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)离子初始质量浓度均为200 mg/L,吸附剂用量为3 g/L)。

基于纳米碳材料的重金属电化学检测

面对重金属离子污染问题,开发快速且准确的重金属离子检测器具有重要意义,碳纳米材料因其易修饰、灵敏度高,常用于电化学检测重金属。此外,碳纳米材料还具有高稳定性、使用寿命长等优点,同时也存在形貌调控困难、传感效率低等问题。通常对碳材料进行官能团修饰或与其他材料复合等,加强其作为电化学传感器的传感效果。依据当前研究现状,主要介绍不同形貌碳纳米材料,如碳纳米管、碳纳米片、石墨烯等,以及其复合材料对重金属离子检测的研究前沿和动态。最后,对碳基纳米材料电化学检测重金属进行展望。

基于金属纳米团簇的荧光传感器在食品安全检测中的应用研究进展

食品安全事件频繁发生,给人类健康造成了极大的威胁和危害,为保证食品的品质与安全,建立灵敏、准确、快速、简单易操作的检测方法尤为重要。金属纳米团簇作为一种荧光纳米材料,具有光稳定性、生物相容性、低毒性等优点,已被广泛应用于细胞标记、生物成像、分析检测等领域。以食源性致病菌、抗生素残留、重金属离子3种广泛存在且毒性较大的食品污染物为例,本文概述了荧光金属纳米团簇在食品安全检测中的应用,包括不同荧光金属纳米团簇的制备方法、对目标物的传感机制、传感器的性能等内容,重点介绍了金属纳米团簇与目标分析物间的相互作用机制,以期为食品中污染物荧光检测法的构建提供一定的理论基础,同时为进一步拓展金属纳米团簇在食品分析检测领域的应用提供新的思路。

基于特异性识别元件的电化学传感器在食品中重金属检测的研究进展

重金属污染是造成食品安全问题的重要原因之一,同时,重金属检测体系复杂,干扰因素较多,因此开发高效、抗干扰强、操作简便的重金属检测方法是至关重要的。电化学传感技术操作简便、灵敏度高,响应快,在重金属检测中应用广泛,而将特异性识别元件与电化学传感技术结合可以进一步提高其在实际样品中检测重金属的抗干扰性。该文综述了特异性识别元件主要包括脱氧核酶、适配体和离子印迹聚合物及其区别,并介绍了基于特异性识别元件的电化学传感器在食品中重金属(主要包括Pb^(2+)、As^(3+)、Cd^(2+)、Cr^(3+)/^(6+))检测的应用。此外,对特异性识别元件在重金属检测领域做出展望,为后续研究提供参考。

MOFs基电化学传感器及其重金属离子检测应用研究进展

现代工业化快速发展,重金属等环境污染严重影响公众健康和生态系统安全。基于MOFs及其复合材料的电化学传感系统是重金属污染物分析检测领域的研究热点。综述了基于MOFs及其复合材料的电化学传感器的构建及其在重金属离子检测中的应用研究进展,简要概述了MOFs材料的组成、结构、分类命名、制备技术、电化学传感优势性能等;探讨了MOFs/碳纳米材料、MOFs/金属纳米材料和MOFs/导电聚合物复合材料应用于电化学传感器的优势特性;详细讨论了MOFs基电化学传感器在Pb^(2+)、Hg^(2+)和Gd^(2+)等重金属离子检测方面的应用研究进展;对MOFs基电化学传感器在重金属离子检测应用中的优势及存在的问题进行了分析,并对未来研究发展趋势进行了展望。

基于席夫碱的重金属离子荧光传感器的研究进展

席夫碱因其独特的电子化学结构,使其能够在众多的研究领域得到应用,尤其是席夫碱在与不同的金属离子结合时能够产生稳定的配合物,其出色的配位能力使其在识别不同金属阳离子方面表现出了卓越的性能,被用作荧光开/关化学传感器用于检测材料中的各种重金属离子。就席夫碱型化学传感器对部分重金属离子的检测应用进行介绍,对其用于不同重金属离子的检测性能进行归纳,以展示基于席夫碱的各种重金属离子化学传感器的研究进展,为基于席夫碱的新型重金属离子荧光化学传感器的设计提供一定的理论基础。