Highly selective and sensitive fluorescent chemosensor for Hg in aqueous solution

A new indole-based fluorescent chemosensor 1 was prepared and its metal ion sensing properties were investigated. It exhibits high sensitivity and selectivity toward Hg²⁺ among a series of metal ions in H₂O-EtOH (7:1, v/v). The association constant of the 1:1 complex formation for 1-Hg²⁺ was calculated to be 9.57 × 10³ M⁻¹, and the detection limit for Hg²⁺ was found to be 2.25 × 10⁻⁵ M. Computational results revealed that 1 and Hg²⁺ ion formed with a central tetrahedron-coordinated Hg²⁺.     

Multifunctional Core–Shell Upconverting Nanoparticles for Imaging and Photodynamic Therapy of Liver Cancer Cells

Lanthanide‐doped upconversion nanoparticles (UCNPs) have attracted considerable attention for their application in biomedicine. Here, silica‐coated NaGdF₄:Yb,Er/NaGdF₄ nanoparticles with a tetrasubstituted carboxy aluminum phthalocyanine (AlC₄Pc) photosensitizer covalently incorporated inside the silica shells were prepared and applied in the photodynamic therapy (PDT) and magnetic resonance imaging (MRI) of cancer cells. These UCNP@SiO₂(AlC₄Pc) nanoparticles were uniform in size, stable against photosensitizer leaching, and highly efficient in photogenerating cytotoxic singlet oxygen under near‐infrared (NIR) light. In vitro studies indicated that these nanoparticles could effectively kill cancer cells upon NIR irradiation. Moreover, the nanoparticles also demonstrated good MR contrast, both in aqueous solution and inside cells. This is the first time that NaGdF₄:Yb,Er/NaGdF₄ upconversion‐nanocrystal‐based multifunctional nanomaterials have been synthesized and applied in PDT. Our results show that these multifunctional nanoparticles are very promising for applications in versatile imaging diagnosis and as a therapy tool in biomedical engineering.     

Electrochemical Sensor for Sensitive Determination of Ga(III) Ion Based on β‐Cyclodextrin Incorporated Multi‐walled Carbon Nanotubes and Imprinted Sol‐gel Composite Film

A novel sensor for detection of trace gallium ion [Ga(III)] was created by stepwise modification of a gold electrode with β‐cyclodextrin (β‐CD)/multi‐walled carbon nanotubes (MWCNTs) and an ion imprinted polymer (IIP). The sensor surface morphology was characterized by scanning electron microscopy. The electrochemical performance of the imprinted sensor was investigated by cyclic voltammetry, differential pulse voltammetry and chronoamperometry. The sensor displayed excellent selectivity towards the target Ga(III) ion. Meanwhile, the introduced MWCNTs displayed noticeable catalytic activity, and β‐CD demonstrated significant enrichment capacity. A linear calibration curve was obtained covering the concentration range from 5.0×10^?8 to 1.0×10^?4 mol·L^?1, with a detection limit of 7.6×10^?9 mol·L^?1. The proposed sensor was successfully applied to detect Ga(III) in real urine samples.     

Functionalized polypyrrole nanotube arrays as electrochemical biosensor for the determination of copper ions

A novel electrochemical biosensor based on functionalized polypyrrole (PPy) nanotube arrays modified with a tripeptide (Gly-Gly-His) proved to be highly effective for electrochemical analysis of copper ions (Cu²⁺). The vertically oriented PPy nanotube arrays were electropolymerized by using modified zinc oxide (ZnO) nanowire arrays as templates which were electrodeposited on indium–tin oxide (ITO) coated glass substrates. The electrodes were functionalized by appending pyrrole-α-carboxylic acid onto the surface of polypyrrole nanotube arrays by electrochemical polymerization. The carboxylic groups of the polymer were covalently coupled with the amine groups of the tripeptide, and its structural features were confirmed by attenuated total reflection infrared (ATR-IR) spectroscopy. The tripeptide modified PPy nanotube arrays electrode was used for the electrochemical analysis of various trace copper ions by square wave voltammetry. The electrode was found to be highly sensitive and selective to Cu²⁺ in the range of 0.1–30 μM. Furthermore, the developed biosensor exhibited a high stability and reproducibility, despite the repeated use of the biosensor electrode.     

金橙G螯合形成树脂分离富集地质样品中的微量贵金属

主要研究了金橙Ｇ螯合形成树脂分离富集地质样品中金、铂、钯的最佳实验条件。在柱高大于１６ｃｍ，０．１ｍｏｌ／Ｌ ＨＣｌ介质的样品溶液以小于或等于０．５ｍＬ／ｍｉｎ流速过柱，用０．１ｍｏｌ／Ｌ ＨＣｌ的３％硫脲溶液以小于或等于０．５ｍＬ／ｍｉｎ流速洗脱金、铂、钯（和铑），都能同时定量富集。用火焰原子吸收光谱法测定，回收率均在９５％￣１１０％之间。经地质样品加标准回收实验，结果令人满意。证明这种以磺酸基     

膨胀石墨/聚苯胺/Fe_3O_4复合材料的制备及吸波性能

采用原位聚合方法制备了膨胀石墨/聚苯胺(EG/PANI)复合材料,将Fe_3O_4负载于EG/PANI表面,得到具有电磁吸收性能的EG/PANI/Fe_3O_4复合材料.通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)及矢量网络分析仪(VNA)等对复合材料的形貌、成分和吸波性能进行了研究.吸波性能分析结果表明,当掺杂浓度为0.05 mol/L,匹配厚度d=2 mm时,样品的最小反射损耗(RLmin)在8.64 GHz处达到-37 dB.随着掺杂浓度的增加,最小反射损耗峰向低频移动,对应的匹配厚度逐渐变厚.材料的介电弛豫极化、涡流损耗及λ/4模型的干涉相消现象出现的双峰,使EG/PANI/Fe_3O_4复合材料在电磁波吸收领域有一定的应用前景.     

Promoted colorimetric response of spirooxazine derivative: a simple assay for sensitive mercury(II) detection

Research on Chemical Intermediates - A spirooxazine derivative 1,3-dihydro-1,3,3-trimethyl-spiro[2-H-indole-2-2′-[2H-1,4] oxazino [2,3-f] [1, 10] phenanthroline] (compound 1) was explored as...     

亚微米级Cu0/Fe3O4复合物多相催化过一硫酸盐降解有机污染物

过一硫酸盐催化活化技术因其可产生强氧化性活性氧化物种,可快速氧化降解并矿化有机污染物的优异性能而备受关注.本文成功制备了亚微米级Cu0/Fe3O4复合物,发现其能多相催化过一硫酸盐产生单线态氧降解有机污染物.首先,以CuCl2·2H2O,FeCl2·4H2O和FeCl3·6H2O为铜源和铁源,水合肼为还原剂,采用水热法在180oC反应24 h制备了亚微米级磁性Cu0/Fe3O4复合物.表征结果显示,所制材料为Cu0和Fe3O4的复合物,颗粒大小约为220 nm;单一相Cu0和Fe3O4晶体粒径分别为33.8和106.2 nm,而Cu0/Fe3O4复合物中Cu0和Fe3O4晶体粒径分别减为20.8和31.9 nm.这表明Cu0和Fe3O4复合降低了Cu0和Fe3O4晶体粒径,有利于Cu0和Fe3O4的分散.BET测试结果表明,Cu0/Fe3O4复合物比表面积为4.6 m2/g,与Cu0颗粒的(4.2 m2/g)相当,但远小于Fe3O4的(15.6 m2/g).制备的Cu0/Fe3O4复合物可有效催化过一硫酸盐产生单线态氧降解罗丹明B、亚甲基蓝、金橙II、苯酚和对氯酚.当Cu0/Fe3O4复合物的用量为0.1 g/L,过一硫酸盐浓度为0.5 mmol/L和初始pH为7时,Cu0/Fe3O4复合物可在30 min内完全降解20μmol/L的罗丹明B、亚甲基蓝、金橙II以及0.1 mmol/L的苯酚和对氯酚.对比试验显示,在相同条件下,Cu0和Fe3O4颗粒分别可以降解28%和20%的罗丹明B.这表明Cu0/Fe3O4复合物中的Cu0和Fe3O4晶体在催化过一硫酸盐降解污染物的反应中具有协同作用,这主要来源于Cu0/Fe3O4复合物中Cu0和Fe3O4的晶体粒径变小和更好的分散.采用分光光度法测定了降解反应液中铜和铁离子的溶出量.当Cu0/Fe3O4复合物的用量为0.1 g/L,过一硫酸盐浓度为0.5 mmol/L和初始pH为7时,反应60 min后,降解液中铜和铁离子的浓度分别为0.22和0.1 mg/L,仅占复合物中总铜和总铁量的1.1%和0.2%,表明Cu0/Fe3O4复合物具有较强的化学稳定性.所制Cu0/Fe3O4复合物具有超顺磁性,借助磁场实现快速分离回收,可循环利用五次,表明其优越的催化稳定性.通过加入乙醇和叠氮化钠,考察了Cu0/Fe3O4复合物催化活化过一硫酸盐体系中的活性氧化物种.发现100 mmol/L乙醇的加入对污染物的降解无明显影响,而加入同等量的叠氮化钠可完全抑制污染物的降解,表明Cu0/Fe3O4复合物催化活化过一硫酸盐产生的主要活性氧物种为单线态氧.采用电子顺磁共振谱进一步证实了单线态氧的生成.基于以上研究,Cu0/Fe3O4复合物催化活化过一硫酸盐的机理为Cu0/Fe3O4作为一个电子媒介加速过一硫酸盐和污染物之间的电子转移,从而导致污染物被快速降解.该反应机理不同于常见的金属催化过一硫酸盐产生硫酸根和羟自由基的反应机理.我们推测,电导性优良的Cu0在此催化反应中起着关键性作用.本催化方法可作为一种绿色的氧化技术用于环境污染物的氧化降解处理.     

TiO2@Ag修饰的粉煤灰微集料增强水泥基材料光催化性能

自清洁和空气净化能力是绿色建筑发展的两个重要方向,它们不仅使建筑体向功能多样化方向发展,而且为新材料的应用提供了平台.因与大量城市环境污染物(氮氧化物,挥发性有机化合物等)直接接触,具有空气净化能力的光催化水泥基材料引起了人们广泛关注.在过去几十年里,通过使用直接喷洒到浆体表层或与水泥原材料预先共混的方法,国内外已相继将TiO2光催化材料应用到了一些实际工程中.但TiO2光催化剂在水泥基材料中高效和稳定发挥其性能仍需解决两个关键问题:(1)它在水泥基体中分散性和效能耐久性问题;(2)其量子效率和对可见光利用率问题.对于后者,目前的材料制备与改性方法,如金属、非金属改性等已能获得量子效率和可见光活性都较好的TiO2类光催化材料.研究表明,水泥水化产物(氢氧化钙、C-S-H凝胶等)的包覆、后期碳化所致气体和光线扩散孔隙的降低是导致TiO2光催化剂在水泥基材料中耐久性和利用率差的可能原因.我们前期报道了一种将纳米TiO2催化剂预先负载到水泥基材料用的多孔粗集料表面,然后将负载型催化剂整体引入到水泥基体中的催化剂应用方法,发现该法能有效提升TiO2催化剂在水泥基材料中的催化效率和耐久性.微米级活性粉煤灰具有良好的水泥基材料兼容性,通过采用简单的碱激发手段,可形成孔径小于50 nm的介孔和微孔类沸石材料,从而影响光催化材料的催化性能.因此,基于粉煤灰的特征,为了进一步提高TiO2催化剂在水泥基材料中的应用效率和催化耐久性,我们采用碱激发法获得了大比表面和介孔结构的沸石类粉煤灰材料,将其用于负载纳米TiO2催化剂,然后引入到水泥基体中,制备了沸石类粉煤灰/TiO2光催化水泥基材料,同时研究了光还原Ag修饰对沸石类粉煤灰/TiO2光催化水泥基材料的催化性能影响及其催化耐久性.结果表明,具有分级孔结构的沸石粉煤灰载体可有效提升纳米TiO2光催化剂在水泥基体中的暴露度,同时还增加了其对气相苯(200×10–6初始浓度)的光催化去除能力.最佳Ag修饰量(1.4×10–4 wt%)沸石类粉煤灰/TiO2光催化水泥样品对气相苯的光催化伪一级反应速率常数达到9.91×10–3 min?1,分别是沸石类粉煤灰/TiO2光催化水泥样品和纯TiO2光催化水泥样品效能的3和10倍.光催化稳定性结果发现,在3次催化循环后,样品对气相苯的光催化去除率仍能达到96.3%(180 min).考虑到水泥基材料碳化是影响光催化剂使用耐久性的一个关键因素,我们还评估了沸石类粉煤灰/TiO2光催化水泥样品28 d加速碳化后的光催化性能.结果表明,经过加速碳化后,样品对气相苯光催化去除率只降低了11%,相比于同条件下纯TiO2水泥样品性能,其催化耐久性显著提高,表明沸石类粉煤灰载体可有效提升TiO2在水泥基体中的催化耐久性.这可能是由于其高孔隙特性可降低周围水泥水化产物的形成量,如高钙/硅比C-S-H凝胶及氢氧化钙结晶,进而降低了这些水化产物碳化所带来的影响.     

单滴微萃取-气相色谱质谱联用法测定纺织品中可分解芳香胺

建立了单滴微萃取结合气相色谱-质谱法测定纺织品中可分解芳香胺的方法。研究了萃取剂种类、萃取剂体积、萃取时间、pH和搅拌速度等条件对单滴微萃取效率的影响。确定最佳萃取条件:在室温条件下,取5 mL样液,调节被萃取液pH8,以2μL氯苯为萃取剂萃取20 min,搅拌速度为200 r/min。在优化的实验条件下,检出限为0.08~0.14 mg/kg,线性范围0.5~50 mg/kg,线性相关系数大于0.996,平均加标回收率为75.3%~96.7%,相对标准偏差为3.6%~8.7%。方法适合纺织品中可分解芳香胺的测定。