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。     

基于介孔碳的电化学酪氨酸酶生物传感器法测定水体中的苯酚及高效液相色谱法评价

采用新型的介孔碳材料作为固载酪氨酸酶的检测平台构建生物传感器,应用于水体环境中苯酚污染物的检测,并通过高效液相色谱法对电化学酪氨酸酶生物传感器法的准确性进行了评价。研究表明,介孔碳的"空间限制效应"能够防止酪氨酸酶(三维尺寸为6.5 nm×9.8 nm×5.5 nm)体外去折叠失活。基于介孔碳材料构建的电化学酪氨酸酶生物传感器在苯酚污染物检测方面显示了优良的性能,其重现性、灵敏度、稳定性、选择性以及检出限均比较令人满意。基于介孔碳的电化学酪氨酸酶生物传感器对苯酚污染物的检出限达到20 nmol/L,线性范围为0.1~10 μmol/L。采用基于介孔碳的电化学酪氨酸酶生物传感器和高效液相色谱法对实际水样品进行测定结果比对,结果表明该生物传感器方法检测结果准确、有效,适合于苯酚污染物突发污染事件的应急检测。     

核酸介导信号放大光学生物传感器在食品污染物检测中的应用EI北大核心CSCD

信号放大是新型生物传感分析过程中重要的环节。核酸介导的信号放大技术凭借核酸材料灵活的结构设计、低成本和易于制备等特点,在生物传感快速检测技术的开发上逐渐发展成为一项重要的分支,广泛应用于食品、环境和医药等新型检测方法开发。介绍了传统和新型核酸扩增技术、生物条形码和DNA walker等信号放大机理和应用,同时进一步综述核酸信号放大技术结合光学生物传感在食品污染物中检测的应用,如化学污染物、毒素类污染物、和重金属污染物等,并对核酸介导的信号放大技术在食品污染物检测中的问题和前景进行讨论。     

核酸适配体生物传感器在三聚氰胺检测中的应用进展

三聚氰胺常被非法添加到食品中,以提高食品中蛋白质的含量。但是,三聚氰胺一旦进入体内,会对人们的健康造成伤害。因此,对三聚氰胺的检测十分必要。为了弥补传统仪器检测法和免疫检测法的不足,基于核酸适配体开发了一系列新的生物传感器,用于三聚氰胺的检测。按照与三聚氰胺的不同识别机制,把这些新的生物传感器分成了四类,分别为基于多聚胸腺嘧啶DNA链和三聚氰胺识别的生物传感器、基于无嘌呤位点的三链DNA结构和三聚氰胺识别的生物传感器、基于核酸适配体和三聚氰胺识别的生物传感器、基于三聚氰胺和汞离子/铜离子等配位识别的生物传感器。本文按照上述四类方法逐个展开,对核酸适配体生物传感器在三聚氰胺检测中的应用进行了综述,并对它们的优缺点进行阐述。     

第3届食品分析最新进展国际专题会议(Ⅲ)

鉴于食品分析的重要性, 特再补充报道如下: 总论组的报告有: (1) M Verissimo, 我们能否认可饮用水的质量? -应用声波传感器测定Al;(2) N I Prisimovic等, 采用专用的色变技术、 直接检测食品质量的下降;(3) W Van Dongen, 评估食品安全的分析战略;(4) T G Lana, 供电流检测葡萄糖用的: Cu改性电极的优化;(5) L Muresan, 以胺氧化酶为主的电流检测生物传感器-应用于液相色谱技术检测来源于生物的胺;     

电化学生物传感器在环境监测中的应用及发展前景

简要介绍了电化学生物传感器的工作原理,重点论述了电化学生物传感器在环境监测领域的应用及其研究进展,主要包括水环境污染物和大气污染物的监测,以及农药残留的监测等.同时,对电化学生物传感器的发展方向及前景进行了展望.     

磁弛豫开关传感器在医学诊断及食品安全检测中的研究进展

临床生化或食品复杂体系样本的快速、准确检测对于保障人类健康有重要意义。基于磁性纳米粒子的磁弛豫开关传感器是集纳米、核磁共振、化学、生物免疫分析技术于一体的的新型传感器,具有快速、无损、灵敏、特异性强、可检测浑浊溶液样品等优点。本文在简述超顺磁弛豫开关传感器检测原理的基础上,对MRS的检测目标物、传感器构造特点、检测灵敏度及检测过程中T_2的变化规律进行了归纳总结,对其应用于检测多种医学诊断生物标志物和食品中重要有害因子的研究进行了评述,并从磁纳米粒子的制备与修饰、磁弛豫开关传感器检测灵敏度的提高及高通量磁弛豫传感器的构建等方面提出了解决策略。     

亚硝酸盐电化学传感器研究进展

亚硝酸盐被广泛用于工业和农业生产,在食品、饮用水、生物和环境中普遍存在。但是,亚硝酸盐是一种有毒的污染物,对人体有很大的危害。近年来发展了很多检测亚硝酸盐的方法,其中电化学法由于具有简单、快速、灵敏、价格低廉等优点而备受青睐。本文从复合电极修饰层材料的角度,综述了近年来基于碳材料、金属材料、金属有机骨架化合物、导电聚合物、酶的纳米复合电极在检测亚硝酸盐的纳米电化学传感器中的研究进展,重点介绍了电极构建和亚硝酸盐检测方法,对亚硝酸盐电化学传感器的发展前景进行了展望。     

反射式光纤银膜SPR传感器的湿法构建及应用

采用银镜反应湿法制备了反射式光纤表面等离子体共振(Surface plasmon resonance,SPR)传感器,并结合多巴胺自聚合功能对光纤表面银膜进行快速生物功能化修饰,实现了抗体抗原相互结合的在线监测。通过自行搭建SPR仪器,考察了传感区长度的影响,跟踪测定了传感器各个修饰步骤后SPR信号的变化。测试结果表明,该法制备的光纤SPR传感器具有很高的灵敏度。随着传感区长度的增加,基于SPR峰位的检测灵敏度随之增大,而基于SPR峰强的检测灵敏度无明显变化。当传感区长度为1.5 cm时,基于SPR峰位对蔗糖溶液折射率的检测灵敏度为4 166 nm/RIU,而基于SPR峰强的检测灵敏度为99%/RIU。进一步利用该传感器监测了Ig G的连接过程、Ig G抗体-抗原的相互结合过程,结果显示其可应用于生物传感检测领域。     

基于电化学生物传感器的重金属离子检测研究进展

电化学生物传感器是基于抗原抗体、酶、核酸适配体、蛋白质、细胞等各种生物成分建立的电化学方法,由于这些生物成分具有强的特异性,决定了电化学生物传感器具有高选择性。同时该方法还具有便捷快速、灵敏、操作简单等优点,已经被广泛应用于污染物重金属离子的检测,并具有良好的应用前景。本文综述了近年来基于各种生物成分的电化学生物传感器在重金属离子检测中的应用,并对该领域未来的发展趋势做了展望。     

A concept study on non-targeted screening for chemical contaminants in food using liquid chromatography–mass spectrometry in combination with a metabolomics approach

A generic method to screen for new or unexpected contaminants at ppm levels in food has been developed. The method comprises an acidic acetonitrile extraction, detection with ultra-high-pressure liquid chromatography coupled to electrospray ionisation time-of-flight mass spectrometry and statistical evaluation using a metabolomics approach comparing suspected contaminated food with uncontaminated foods. The method was tested for 26 model contaminants from 100 μg/g down to 0.4 μg/g in three brands of fresh orange juice. Blinded statistical evaluation revealed signals from all added contaminants detectable by liquid chromatography–electrospray ionisation using positive ionisation mode, while only two false-positive signals were reported. The method is primarily intended to be used for investigation of food samples suspected to be contaminated with unknown substances. Additionally it could be used to continuously monitor for appearance of new food contaminants as a complement to the specific targeted analysis that is today’s foundation of food safety analysis.     

A single DNA aptamer functions as a biosensor for ricin

The use of microorganisms or toxins as weapons of death and fear is not a novel concept; however, the modes by which these agents of bioterrorism are deployed are increasingly clever and insidious. One mechanism by which biothreats are readily disseminated is through a nation's food supply. Ricin, a toxin derived from the castor bean plant, displays a strong thermostability and remains active at acidic and alkaline pHs. Therefore, the CDC has assigned ricin as a category B reagent since it may be easily amendable as a deliberate food biocontaminate. Current tools for ricin detection utilize enzymatic activity, immunointeractions and presence of castor bean DNA. Many of these tools are confounded by complex food matrices, display a limited dynamic range of detection and/or lack specificity. Aptamers, short RNA and single stranded DNA sequences, have increased affinity to their selected receptors, experience little cross-reactivity to other homologous compounds and are currently being sought after as biosensors for bacterial contaminants in food. This paper describes the selection and characterization of a single, dominant aptamer, designated as SSRA1, against the B-chain of ricin. SSRA1 displays one folding conformation that is stable across 4-63 °C (ΔG = -5.05). SSRA1 is able to concentrate at least 30 ng mL(-1) of ricin B chain from several liquid food matrices and outcompetes a currently available ELISA kit and ricin aptamer. Furthermore, we show detection of 25 ng mL(-1) of intact ricin A-B complex using SSRA1 combined with surface enhanced Raman scattering technique. Thus, SSRA1 would serve well as pre-analytical tool for processing of ricin from liquid foods to aid current diagnostics as well as a sensor for direct ricin detection.     

Optimization of an electrolytic conductivity detector for determination of toxic nitrogen-containing food contaminants separated by open tubular column gas chromatography

The combination of open tubular column gas chromatography with electrolytic conductivity detection has been evaluated for the determination of nitrogen-containing pesticide residues in food extracts. Optimization of the column position at the column-detector interface was crucial to the successful operation of the detector. The signal-to-noise ratio and response stability of the detector are greatly influenced by the composition of the electrolyte solvent. Large volume splitless injections using retention gaps and optimized detector operating conditions enabled pesticide residues in food extracts to be determined at sub parts-per-million levels. Although the electrolytic conductivity detector is less sensitive than the thermionic ionization detector, its greater nitrogen selectivity can he crucial to the determination of nitrogen-containing contaminants in food extracts, particularly in complex mixtures where phosphorus-containing contaminants or matrix compounds are also present.     

纸基食品接触材料中4-肉桂苯酚和水杨酸对叔丁基苯酯向干性食品模拟物TenaxTA的迁移

以纸基食品接触材料中的4-肉桂苯酚(CP)和水杨酸对叔丁基苯酯(TBS)为模拟迁移物,对其向干性食品模拟物Tenax TA中的迁移规律采用超高效液相色谱结合荧光检测(UPLC-FLR)方法进行了研究。在不同温度下对CP和TBS的迁移动力学进行了考察,并对其在封闭环境和敞开环境下的迁移率进行对比研究。通过设计不同质量的Tenax TA接触直径为3.5 cm圆片样品的迁移试验,探索了迁移试验中合适的模拟物质量/接触材料面积比条件。系列试验结果表明,迁移物迁移时间越长,迁移温度越高,相应的迁移率就越高;在高的迁移温度下,迁移物在Tenax TA上的解吸会导致迁移率的下降;在封闭条件下CP和TBS的迁移率要高于敞开条件下的迁移率;迁移试验中,4.16 g/dm²的模拟物质量/接触材料面积比是利用干性食品模拟物进行食品接触材料暴露评估的合适的迁移试验条件。密闭条件下市售的8种食品接触材料干性食品模拟物迁移实验研究表明,TBS存在于用于包装坚果类食品的包装纸中,含量为15.54 mg/kg。     

Application of capillary electrophoresis-mass spectrometry for determining organic food contaminants and residues

Food contamination continues to be a serious problem around the world. Surveillance of chemical contaminants in foods is important not only for public health but also because of the negative economic impact of contamination. From the analytical perspective, analysis of contaminants in food is an extremely challenging area. There is a wide variety of questions, ranging from the quantification of extremely low levels of individual components to the detailed assessment and evaluation of the analytical technique possibilities. This review considers the applications of CE coupled to MS detection (CE-MS) for the analysis of organic contaminants in food. Analytical information on sample concentration techniques, as well as on the CE separation conditions and recoveries obtained from water and food are provided. Different sections include several fields of application, such as pesticides, drug residues, or toxic formed during food processing in different matrices. A number of tables report a comprehensive listing of CE-MS applications. As a result, this work presents an update overview on the principal application of CE-MS together with a discussion of their main advantages and drawbacks, and an outline of future trends on analysis of organic contaminants.     

Challenges in the electrochemical (bio)sensing of nonelectroactive food and environmental contaminants

Electrochemical detection of nonelectroactive contaminants can be successfully faced via the use of indirect detection strategies. These strategies can provide sensitive and selective responses often coupled with portable and user-friendly analytical tools. Indirect detection strategies are usually based on the change in the signal of an electroactive probe, induced by the presence of the target molecule at a modified electrode. This critical review aims at addressing the developments in indirect electrosensing strategies for nonelectroactive contaminants in food and environmental analysis in the last few years. Emphasis is given to the strategy design, the electrode modifiers used and the feasibility of technological transfer.     

Quantitative determination method for trace amount of penicillin contaminants in commercially available drug product by HPLC coupled with tandem mass spectrometry

A quantitative determination method for trace amount of penicillin contaminants in an active pharmaceutical ingredient (API) has been developed. Selective extraction of penicillin contaminants from the matrix containing API and specific separation among penicillin contaminants were achieved through an on-line column switching technique with gradient elution, followed by tandem mass spectrometric determination. Validation was conducted on the developed method in terms of specificity, linearity, accuracy, precision, and detection limit, and appeared reasonable. The detection limit was estimated as 0.03 ng/ml or lower of the concentration of penicillin contaminants in the preparation, corresponding to 4 parts par billion (ppb) against the API. This fulfilled the regulatory requirement by the authorities.     

表面增强拉曼光谱技术在食品安全检测中的应用

表面增强拉曼光谱是一种强有力的食品检验技术,当待测样品吸附于具有纳米量级粗糙度的金属结构表面时,样品分子的拉曼信号将得到极大的增强。该检测技术具有灵敏度高、响应迅速以及"指纹"识别等特点,在快速检测食品污染物等方面具有巨大的应用前景。该文介绍了表面增强拉曼光谱技术的发展历史、基本原理、基底分类以及联用技术,综述了该技术在重金属离子、兽药残留、农药残留、非法添加物、食源性致病微生物等方面的最新应用,最后提出了亟需解决的问题与未来的发展趋势(引用文献74篇)。     

冷冻干燥技术在环境水样有机新污染物前处理中的应用进展

有机新污染物是一类在先进分析技术帮助下新鉴定的、现有法规未管制的、人为源的有机污染物。有机新污染物主要包括药品与个人护理、农药、全氟化合物、内分泌干扰物等,其会产生内分泌干扰效应、诱发抗性基因传播,还对人类和野生生物的生存与发展构成潜在威胁,因此检测环境样品中的有机新污染物浓度对生态环境和人体健康具有重大意义。由于环境样品中的有机新污染物浓度较低,为了达到检测仪器的检测要求,通常需要对环境样品进行前处理,包括样品的净化和浓缩。冷冻干燥技术是一种在真空干燥条件下通过升华方式去除水分的前处理技术,主要包括样品冷冻、初级干燥和再干燥3个阶段,常用于食品和药品行业。在药品行业中,冷冻干燥技术能维持药品的生物活性和化学活性,保持药品的物理化学特性。近年来,冷冻干燥技术逐步用于环境水样中有机新污染物的前处理。其主要的操作步骤包括水样预处理、冷冻干燥、洗脱、吹干、过滤、定容和上机检测。冷冻干燥技术具有操作简单、低成本、样品处理体积少、样品易保存和处理过程中样品损失少等优点,具有广泛应用于环境样品中有机新污染物监测的潜力。该文综述了环境样品中有机新污染物常见的种类,并重点介绍冷冻干燥技术的原理及其在环境样品前处理过程中的应用,提出了冷冻干燥技术在环境分析中的应用前景,为环境样品中有机新污染物的监测提供了参考。