燃烧过程中碱/碱土金属对重金属迁移转化影响的研究进展

碱/碱土金属广泛存在于各种固体燃料中，在燃烧过程中碱/碱土金属与燃料中重金属及其他矿物发生复杂的物理化学反应，从而影响重金属的迁移和转化。本研究主要介绍了碱/碱土金属对As、Se、Pb和Cr四种重金属迁移转化的影响规律，包括碱金属和碱土金属对重金属迁移转化的影响，颗粒物团聚与黏结对重金属排放的影响三个方面。碱/碱土金属能够抑制重金属的挥发：碱金属与Cl元素的结合，降低了PbCl₂的生成；碱金属的存在有利于提升高岭土对Pb的吸附效率；碱/碱土金属可以与As和Se形成稳定的化合物。但同时需要注意碱/碱土金属与Cr的部分结合产物中，Cr以六价态存在，具有较高的毒性。碱/碱土金属对于团聚现象发生，分别起到了促进和抑制作用，适当含量的碱金属有利于减少重金属的释放。通过总结碱/碱土金属对重金属迁移转化的影响规律，以期为降低重金属的危害提供思路。     

Sensitive detection of heavy metals ions based on the calixarene derivatives-modified piezoelectric resonators: a review

Heavy-metal pollution is a foremost concern, as excessive heavy metals produce environmental contamination, and the accumulative effects of heavy metals pose a major hazard to human health. There is an urgent need for a fast, sensitive and effective method for detecting heavy metal cations in the environment. In recent years, using Quartz Crystal Microbalance (QCM) technique, significant progress was achieved in quantitative analysis by providing a new approach for determination of chemical content analysis. The objective aim of this review is to assess the research development of QCM applications in detection of heavy metal cations in natural water (or aqueous solution) and reflect the challenges and forthcoming point of view for QCM-based sensors for heavy-metal ions. A brief outline about the basic measurement methodologies and analytical techniques is given. To illustrate applications of the QCM techniques, the influence of the structural transformation resulting from polymer, macrocyclic ‘calixarenes’ and nanostructural coating on sensation will be discussed. Lastly, we summarise fields of applications and future forecast for the utilisation of functionalised QCM surface as a chemical sensor to study the interaction of heavy metal ions with calixarenes.     

Electrochemical machining of metals: Fundamentals of electrochemical shaping

Basic problems of metal electrochemical shaping theory are considered. Exact and approxi1mate (quasi-steady-state, locally one-dimensional) methods for solving direct and inverse problems are analyzed. Experimental methods for improving the electrochemical shaping accuracy are considered.Translated from Elektrokhimiya, Vol. 40, No. 12, 2004, pp. 1438–1480.Original Russian Text Copyright © 2004 by Davydov, Volgin, Lyubimov.     

Electrochemical Biosensing in Cancer Diagnostics and Follow‐up

In cancer, screening and early detection are critical for the success of the patient's treatment and to increase the survival rate. The development of analytical tools for non‐invasive detection, through the analysis of cancer biomarkers, is imperative for disease diagnosis, treatment and follow‐up. Tumour biomarkers refer to substances or processes that, in clinical settings, are indicative of the presence of cancer in the body. These biomarkers can be detected using biosensors, that, because of their fast, accurate and point of care applicability, are prominent alternatives to the traditional methods. Moreover, the constant innovations in the biosensing field improve the determination of normal and/or elevated levels of tumour biomarkers in patients’ biological fluids (such as serum, plasma, whole blood, urine, etc.). Although several biomarkers (DNA, RNA, proteins, cells) are known, the detection of proteins and circulating tumour cells (CTCs) are the most commonly reported due to their approval as tumour biomarkers by the specialized entities and commonly accepted for diagnosis by medical and clinical teams. Therefore, electrochemical immunosensors and cytosensors are vastly described in this review, because of their fast, simple and accurate detection, the low sample volumes required, and the excellent limits of detection obtained. The biosensing strategies reported for the six most commonly diagnosed cancers (lung, breast, colorectal, prostate, liver and stomach) are summarized and the distinct phases of the sensors’ constructions (surface modification, antibody immobilization, immunochemical interactions, detection approach) and applications are discussed.     

微塑料介导重金属在陆生植物中迁移及生物效应的影响

随着地膜在现代化农业中的广泛应用,微塑料在土壤中的残留问题日益严重。环境中释放的微塑料可能会与先前存在的重金属相互作用,导致生物效应(生物积累/毒性),并对人类健康和农产品安全构成威胁。目前,大多数研究集中于单一影响因素在土壤系统中的暴露和转化分析,有关微塑料和共存金属对环境联合影响的相当有限。本文综述了微塑料与重金属来源、相互作用机理与影响因素的研究现状,阐述了陆生植物对二者联合污染的生理响应。此外,未来的研究还应重点探讨微塑料与重金属共同在植物上暴露的具体分子机制、通过食物链对人类健康的影响、与其他混合污染物联合作用及微塑料老化过程对重金属迁移动态变化过程的影响。     

Adsorption of a few heavy metals on natural and modified kaolinite and montmorillonite: a review

The feasibility of using two important and common clay minerals, kaolinite and montmorillonite, as adsorbents for removal of toxic heavy metals has been reviewed. A good number of works have been reported where the modifications of these natural clays were done to carry the adsorption of metals from aqueous solutions. The modification was predominantly done by pillaring with various polyoxy cations of Zr4+, Al3+, Si4+, Ti4+, Fe3+, Cr3+or Ga3+, etc. Preparation of pillared clays with quaternary ammonium cations, namely, tetramethylammonium-, tetramethylphosphonium- and trimethyl-phenylammonium-, N'-didodecyl-N, N'-tetramethylethanediammonium, etc, are also common. Moreover, the acid treatment of clays often boosted their adsorption capacities. The adsorption of toxic metals, viz., As, Cd, Cr, Co, Cu, Fe, Pb, Mn, Ni, Zn, etc., have been studied predominantly. Montmorillonite and its modified forms have much higher metal adsorption capacity compared to that of kaolinite as well as modified-kaolinite.     

Analytical approaches on some selected toxic heavy metals in the environment and their socio-environmental impacts: A meticulous review

Heavy metals are a group of metals and metalloids that have relatively high density and are toxic even at ppb levels. The excess intake of heavy metals in human bodies though the environment may cause various humans health problems. Analytical approaches of some selected toxic heavy metals in the environment and their socio-environmental impacts are discussed in this review. In this present investigation, we have also discussed the design and development of nanomaterials for the detection of metal ions along with kinetic approaches. The isolation or pre-concentration and determination of heavy metals from complex matrices become challenging for analytical chemists and researchers. The fundamentals on sample preparation and analysis of some selected heavy metals employing different analytical tools for qualitative and quantitative determination of these pollutants in real samples are also discussed. In addition, this compiled work enhanced our knowledge in learning about pathway mechanisms and the degree of their risk assessment.     

Layer double hydroxides (LDHs)- based electrochemical and optical sensing assessments for quantification and identification of heavy metals in water and environment samples: A review of status and prospects

One of the most severe environmental problems is heavy metal contamination, putting the world's sustainability at risk. Much effort has been put into developing sensors that can be taken anywhere to detect the environmental effects of heavy metals. Sensitivity, selectivity, multiplexed detection ability, and mobility enhance significantly when nanoparticles and nanostructures are incorporated into sensors. LDHs (layered double hydroxides) have gotten much attention in analytical chemistry in recent years because of their benefits, including their large specific surface area, ease of synthesis, low cost, and high catalytic efficiency and biocompatibility. LDHs are often manufactured as nanomaterial composites or created with specialized three-dimensional structures depending on the application. However, in these settings, LDHs (as color indicators, extracting sorbents, and electrochemical sensing) are usually restricted. Upcoming signs of progress and development possibilities of LDHs in analytical chemistry are reviewed in this paper to assist overcome these problems. Furthermore, the approaches used in the design of LDHs, including structural aspects, are defined and assessed in preparation for future analytical applications. The latest advances in optical and electrochemical sensors to detect heavy metals are described in this review. The sorts and characteristics of LDHs will be explored first. We will then go into microelectrode (or nanoelectrode) arrays, nanoparticle-modified electrodes, and microfluidic optical and electrochemical sensing assays in detail. This paper also discusses design strategies for LDH-based nanostructured sensors and the advantages of using nanomaterials and nanostructures.     

纳米材料电化学与生物传感器——有机微污染物检测新途径

本文介绍了近年来纳米材料电化学与生物传感器在有机微污染物检测中的研究现状,分析了这些传感器中纳米材料修饰电极的特点,重点阐述了纳米材料在有机微污染物检测中的重要作用,列举了一些纳米材料电化学与生物传感器在有机微污染物检测中的应用。最后对纳米材料电化学与生物传感器用于有机微污染物的检测研究进行了简要评述和展望。     

Zinc oxide nanostructured platform for electrochemical detection of heavy metals

ZnO nanoparticles (ZnO-NP) were prepared by a facile precipitation technique using di-isopropyl amine as precipitating agent. The morpho-structure and porosity of the as-prepared nano-powder were investigated by FT-IR analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET analysis. By drop-casting, a composite film was deposited to obtain ZnO-NP-Nafion/GCE modified electrode. The modified electrode was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and square wave anodic stripping voltammetry (SWASV) for the detection of Pb²⁺, Cd²⁺, Cu²⁺, and Fe³⁺, and it was successfully applied for the detection of Pb²⁺ and Cu²⁺ in real water samples.     

A Novel Photo‐Induced Electrochemical Biosensing Method Based on Fluorescent Labeled Molecular Beacon

A novel photo‐induced electrochemical biosensing method has been developed based on fluorescence quenching effect and electrochemical method. In this sensing strategy, the molecular beacon probes labeled with methylene blue were immobilized on the gold nanoparticles modified gold electrode surface firstly; then dopamine was assembled on the electrode surface through electrostatic interaction with gold nanoparticles. Under the continuous illumination, the fluorescence of the methylene blue was quenched by the gold nanoparticles before hybridization; after hybridization with the complementary DNA, methylene blue was far away from the gold nanoparticles and the fluorescence recovered, and then singlet oxygen was generated in the photosensitive reaction of methylene blue in the presence of dissolved oxygen. Singlet oxygen reacted with dopamine, which resulted in the reduction of concentration of the dopamine on the electrode surface. The current of the dopamine on the electrode was used for the sensing of the conformational change of molecular beacon and hence for the detection of target DNA.     

Electrochemical detection of thiols in biological media

The utilisation of catechol as an electrochemical indicator for the presence of sulphydryl thiols (RSH) has been investigated. The electrochemical oxidation of the catechol within tissue culture media was examined with the influence exerted on the redox chemistry by cysteine evaluated in terms of the development of an analytical protocol. The electro-generation of o-quinone was found to be followed by a 1,4-addition reaction with available cysteine such that an increase in the current, attributed to the re-oxidation of the thiol-catechol adduct, could be exploited as means of quantifying the concentration of the thiol. The selectivity of the reaction has been assessed with no interference from lysine, tyrosine, methionine or cystine. Other amino acids possessing sulphydryl thiol functionalities (homocysteine and glutathione) were, however, found to react through a similar route to that observed with cysteine.     

赭曲霉毒素A的电化学适体传感检测

赭曲霉毒素A （OTA）是一类主要由曲霉属和青霉属等真菌产生的小分子有毒次级代谢产物,广泛存在于食品、农产品和动物饲料中,具有强烈肝毒性、肾毒性、致畸和致突变等作用,亦是ⅡB类致癌物。鉴于OTA污染的普遍性和危害性,本文就目前OTA的常用检测方法进行概述和比较,重点阐述新型电化学适体传感技术在OTA检测方面的相关应用。全面综述了构型变换型、亲合型以及混合型OTA电化学适体传感器的原理、优缺点及最新研究进展,并对OTA电化学适体传感器的未来发展方向提出展望,为电化学适体传感器的深入研究与应用提供参考。     

Electrochemical sensing of bisphenol A on single-walled carbon nanotube paper electrodes

The electrochemical detection of BPA often requires modification of electrodes to overcome BPA′s slower kinetics and higher oxidation potential. This work reports a modification-free, paper electrode based on vacuum-filtered SWCNT thin film. The prepared electrode does not need to be polished or transferred into the conducting substrates. The linear sweep voltammetric detection showed a linear response from 0.5–10 μM and 25–100 μM with the experimental LOD of 1.0 μM (S/N=3). The interference study and good recovery percentage (93–105 %) in real water samples demonstrated the method‘s selectivity. The sensor can be promising for developing a simple, low-cost, portable, and paper-based BPA monitoring system.     

A new resin containing benzimidazolylazo group and its use in the separation of heavy metals

A new resin incorporating benzimidazolylazo group into a matrix of polystyrene divinylbenzene has been prepared. The exchange capacity of the resin for the ions mercury(II), silver(I) and palladium(II) as a function of pH has been determined. The resin exhibits no affinity for alkali or alkaline earth metals. It is highly selective for Hg(II), Ag(I) and Pd(II). In column operation, it has been observed that Hg(II), Ag(I) and Pd(II) in trace quantities can be selectively separated from geological, medicinal and environmental samples.     

Monitoring and statistical evaluation of heavy metals in airborne particulates in Cairo, Egypt

Airborne particulate material was monitored as total suspended particles and particulate matter less than 10 μm at selected sites in Cairo. The selected sites represent heavily industrial and industrial–residential areas of Cairo, Egypt. The filters were further analyzed for lead, cadmium, zinc and nickel using ion chromatography. The chosen method was modified to improve resolution and decrease the retention time. The data obtained were treated statistically using one-way analysis of variance and correlated with the anthropological and industrial activities of the sites. The concentrations of the heavy metals are studied in terms of particle size, time dependence, and safety.     

Selective extraction of toxic heavy metals and biological activity studies using pyrimidylthioamide functionalised calix[4]arene

The current study comprises synthesis of pyrimidylthioamide derivatized calix[4]arene (5), and its comparative liquid–liquid extraction properties with the compound 4 towards the selected transition metal ions (Cu²⁺, Co²⁺, Ni²⁺, Pb²⁺, Hg²⁺ and Cd²⁺) were investigated. Experimental results revealed that the compound 5 shows better efficiency and affinity for Pb²⁺ and Hg²⁺ ions as compared to compound 4. The antibacterial and antifungal effects of compound 5 were also investigated on various bacteria and fungi. It has been observed that compound 5 has some effects against Salmonella typhimurium NRRLB 4420, Bacillus cereus ATCC 11778, Staphylococcus aureus NRRL B767 and Bacillus subtilis NRS 744.     

Sample handling in surface sensitive chemical and biological sensing: A practical review of basic fluidics and analyte transport

This paper gives an overview of the advantages and associated caveats of the most common sample handling methods in surface-sensitive chemical and biological sensing. We summarize the basic theoretical and practical considerations one faces when designing and assembling the fluidic part of the sensor devices. The influence of analyte size, the use of closed and flow-through cuvettes, the importance of flow rate, tubing length and diameter, bubble traps, pressure-driven pumping, cuvette dead volumes, and sample injection systems are all discussed. Typical application areas of particular arrangements are also highlighted, such as the monitoring of cellular adhesion, biomolecule adsorption–desorption and ligand–receptor affinity binding. Our work is a practical review in the sense that for every sample handling arrangement considered we present our own experimental data and critically review our experience with the given arrangement. In the experimental part we focus on sample handling in optical waveguide lightmode spectroscopy (OWLS) measurements, but the present study is equally applicable for other biosensing technologies in which an analyte in solution is captured at a surface and its presence is monitored. Explicit attention is given to features that are expected to play an increasingly decisive role in determining the reliability of (bio)chemical sensing measurements, such as analyte transport to the sensor surface; the distorting influence of dead volumes in the fluidic system; and the appropriate sample handling of cell suspensions (e.g. their quasi-simultaneous deposition). At the appropriate places, biological aspects closely related to fluidics (e.g. cellular mechanotransduction, competitive adsorption, blood flow in veins) are also discussed, particularly with regard to their models used in biosensing.     

蛋白质磷酸化作用的电化学检测方法

蛋白质的磷酸化作用是一种可逆的翻译后修饰方式,几乎参与生物体内所有关键生命活动,在核内基因的特定表达、细胞的分裂分化以及各种生命活动的转导中发挥重要意义。基于磷酸化前后电化学信号的改变,利用电化学传感器的方法能快速简便地检测蛋白质的磷酸化作用,且具有较高的选择性和灵敏度。本文回顾了几种常用的电化学检测磷酸化作用的方法,基于电极材料的不同进行了分类与总结,汇总了每种方法中用到的修饰电极的纳米材料及生物分子,最后总结了电化学方法检测蛋白质磷酸化的优缺点,并对有效检测磷酸化作用进行了前景展望。