微流控芯片电泳在食品安全与环境污染检测中的应用

微流控芯片电泳具有样品和试剂消耗量小、分析速度快、分离效率高以及便于微型化等特点,特别适合于食品安全和环境污染相关的现场快速检测。该文综述了微流控芯片电泳技术在食品安全与环境污染检测方面的研究进展,着重介绍了该技术在食品中有害物质残留、非法食品添加剂以及环境样品中有害无机离子、有机污染物等目标物检测方面的典型应用实例,在此基础上初步讨论了微流控芯片电泳走向实际应用面临的问题和可能的解决办法。     

衍生化技术在食品安全色谱分析中的应用

近年来,食品安全问题已成为全球关注的焦点,色谱作为最常用的分析手段被广泛地应用于食品安全检测.然而,色谱方法在检测一些分子量小、极性高、挥发性差、热不稳定、生色基团少的分析物时会遇到检测响应值低、柱上保留时间短等问题,衍生化技术是克服这些问题的常用手段.本文主要介绍食品安全分析中常用衍生化试剂的使用选择和衍生化方法的建立以及衍生化技术在色谱检测食品中真菌毒素、非法添加剂、农兽药残留等物质的应用.     

在线样品制备技术耦合液相色谱-质谱系统在食品危害物检测中的应用进展

食品安全检测具有重要意义,但食品样品基质复杂,测定其中危害物时,通常需要以下几个步骤：样品制备,即采用适合的样品前处理方法,在不同基质中将目标物分离出来;分离纯化,利用色谱系统进一步分离纯化目标物;定性定量分析,基于目标化合物的性质选择合适的检测器进行分析。其中样品制备是关键步骤之一,将样品制备过程与液相色谱系统耦合可以实现样品的在线自动化分析。与传统人工处理过程相比,在线分析不仅能够减少人工操作误差,保证良好的精密度和重复性,而且可以降低溶剂消耗,避免样品间交叉污染,同时节约分析时间,提高检测效率。本文主要介绍目前常用的在线样品制备技术,包括在线固相萃取(on-line SPE)、管内固相微萃取(in-tube SPME)、湍流色谱法(TFC),详细阐述了其基本原理和耦合设备。在线样品制备技术耦合液相色谱-质谱系统分为两个维度,主要依赖于阀切换技术,将样品制备(第一维度)和液相色谱系统(第二维度)之间建立物理连接,随后采用相应的检测器进行分析。第一维度的作用主要是去除样品杂质,净化分离目标物,为第二维度对目标物进行定性定量检测做准备。此外,文章对3种在线净化系统适用的不同净化填料进行...     

非甾类抗炎性药物的吸附与分离分析

非甾类抗炎性药物(NSAIDs)以其良好的消炎、解热和止痛等作用,广泛应用于人类疾病的治疗中.非甾类药物参与炎症治疗的同时不能被肝脏完全代谢,大部分母体化合物及其代谢物随人体排出.大量数据表明,在环境中残留的药物会直接或间接的以食品安全问题呈现出来,这成为分析化学、材料化学等诸多领域学科重点研究课题之一.由于NSAIDs的样品基质复杂,待分析组分种类繁多,目标分析物含量低,分析人员往往借助一些样品前处理技术来对其进行吸附与分离分析.总结了近年来非甾类抗炎性药物所呈现的问题,以及目前对环境中NSAIDs的多种分离检测技术,分离检测的核心是萃取材料的选择,并综述了近年来相关对NSAIDs有效吸附分离材料的研究进展,以及对优异吸附分离材料的展望.     

“色谱及其他分离分析技术在食品安全分析中的应用”专栏引言

“民以食为天,食以安为先”。食品安全事关人民群众健康和生命安全,也关系到社会和谐稳定发展大局。近年来食品安全问题日益凸现：“瘦肉精”事件尘埃未落,“染色馒头”、“牛肉膏”、“毒豆芽”、“塑化剂”等等又接踵而来……。据世界卫生组织估计,全球每年发生食源性疾病约十亿人次,食品安全问题已成为人类面临的最大健康问题。因此,食品安全监督检验工作越来越受到重视,各种新颖的食品安全分析检测技术也应运而生。在众多的食品安全检测方法中,色谱技术扮演了十分重要的角色,尤其是色谱芯片、色谱与质谱联用技术等在食品安全分析中的应用大大提高了复杂基质中目标残留物检测的分析速度、灵敏度和准确性。为了集中展示我国科研和质检人员在食品安全质量分析方面的最新成果,《色谱》杂志特此编辑出版了“色谱及其他分离分析技术在食品安全分析中的应用”专栏。我们有幸邀请到活跃在食品安全分析领域的专家、学者撰写相关的学术论文和综述。本专栏的文章中既有资深学者高屋建瓴的综述评论,也有来自质检第一线的案例分析。既有最新热点的介绍和应用领域的扩展,也有集样品富集技术、分离技术、高灵敏检测技术于一体的联用研究。此外,本专栏还前瞻性的报道了基于芯片电泳的食源性物种鉴定的新技术,相信该技术在我国的食品溯源体系建设中会得到快速的发展和普及。 “智慧在此,思想无疆”。希望这期专栏文章所呈现的理念和精髓,以及这些学术思想的碰撞和交融所产生的智慧的火花,能够给读者以启迪和收益,从而为不断提高我国食品安全分析的研究和应用水平,取得创新性的研究成果做出贡献。     

超交联多孔有机聚合物在柱固相萃取中的应用进展

超交联多孔有机聚合物(hypercrosslinked porous organic polymers, HCPs)是一类通过傅-克烷基化反应将芳香结构单元连接而制备得到的新型多孔材料,具有单体来源广泛、比表面积高、成本低廉、合成条件温和及易功能化等优点,广泛应用于气体储存、多相催化、色谱分离和有机污染物去除等领域。近年来,HCPs作为柱固相萃取吸附剂的研究较多,展现出巨大的应用潜力。基于高比表面积、优异的吸附性能、多样化的化学结构和易于化学改性等优点,HCPs材料被成功应用于不同样品基质中多种类型分析物的萃取并表现出优异的萃取性能。根据HCPs的骨架化学结构、目标分析物的性质及两者间的作用机理,我们将HCPs分为疏水型、亲水型、离子型3类,介绍了各种HCPs的特点、合成方法和在柱固相萃取中的应用。基于HCPs与分析物之间的疏水、π-π、亲水、氢键、离子交换等多种相互作用机理,HCPs萃取材料能够高效萃取和选择性富集不同种类的目标分析物,如苯脲类除草剂、氯酚类化合物、硝基咪唑、四环素、酸碱性药物等。将新型HCPs萃取与色谱、质谱等现代分析技术结合的方法已广泛应用于环境监测、食品安全和生...     

色谱分析中样品前处理技术的发展动态

作为现代分析领域的重要手段之一,色谱可用于食品、环境、生物等复杂样品的定性与定量分析。而样品前处理是获得理想色谱分析结果的必要前提,它可有效消除基质干扰、浓缩目标分析物、改善分离效能以及延长色谱仪器使用寿命。本文主要依据2020年4-5月Anal Chem新发表和在线录用的有关论文,讨论色谱分析中涉及样品前处理技术方面的最新发展动态。     

液相色谱-质谱-质谱技术新进展及应用

近年来,由于液相色谱-质谱-质谱(LC-MS-MS)联用新技术的不断出现,LC-MS-MS已成为现代分析手段中必不可少的组成部分.LC-MS-MS联用的优点非常显著,因为气相色谱只能分离易挥发且不分解的物质,而液相色谱则把分离范围大大拓宽了,生物大分子也能分离,LC与高选择性、高灵敏度的MS-MS结合,可对复杂样品进行实时分析,即使在LC难分离的情况下,只要通过MS1及MS2对目标化合物进行中性碎片扫描,则可发现并突出混和物中的目标化合物,显著提高信噪比.     

光电化学传感器的构建及研究进展

光电化学传感器是以光为激发源,光电流或光电压为检测信号,通过电化学、生物识别等手段定量分析待测物与光电流或光电压之间关系的新型技术。其原理是当光照射到光电活性材料时,材料中的电子受到激发,其上面的识别探针捕获目标分析物,引起光电流或光电压变化。当目标物的浓度变化时,光电信号发生相应的变化,两者之间呈现出函数关系,因此,可以通过光电信号变化,来定量测定目标物。在光电化学传感器中,因其激发源(光)与检测信号(电流或电压)的完全分离极大地减少了背景信号的干扰;又因具有响应快速、灵敏度高、设备简单、价格低廉易于微型化等优点,使光电化学传感器在各大领域备受瞩目。本文介绍了光电化学传感器的基本原理、特点、分类及其应用,并对有代表性的研究和发展前景做了总结和评述。     

色谱技术广泛应用于水质检测、食品安全等领域

正色谱法自发明以来经历了整整一个世纪的发展,到今天已经成为最重要的分离分析科学,广泛地应用于石油化工、有机合成、生理生化、医药卫生、环境保护,乃至空间探索等领域。色谱作为一种强大的分离技术与质谱等检测手段的联用也得到了很大发展,GC–MS,HPLC–MS等在兴奋剂检测,食品安全分析等方面应用广泛。1.离子色谱技术有利于水质检测升级随着现代工业的发展,环境保护问题受到全社会的高度关注,水作为自然环境的重要资源其污染问题日益严重。随     

溶剂化的热力学集团展开理论

把二元溶液的过剩内能（excess energy）分成溶剂-溶剂、溶剂-溶质及溶质-溶质相互作用部分。利用集团展开方法给出了二元溶液在正则系综的配分函数的表达式,利用该表达式得到了溶质的偏摩尔内能(partial molar energy)和偏摩尔熵(partial molar entropy)的表达式。在无限稀溶液情形,过剩偏摩尔内能的溶剂-溶剂部分又称重组织内能（reorganization energy）,它反映了溶质存在时对其周围溶剂分子之间的相互作用能的影响。研究表明,在溶质的粒子数密度相对较大时,溶质分子之间的相互作用将影响过剩偏摩尔内能的溶剂-溶剂部分,对于稀溶液,过剩偏摩尔内能的溶剂-溶剂部分与溶质的摩尔分数成线性关系。对低密度二元溶液,溶质的过剩偏摩尔内能和过剩偏摩尔熵也与溶质的摩尔分数成线性关系。     

Call for nominations for the Heinrich-Emanuel-Merck Award

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Call for nominations for the Heinrich-Emanuel-Merck Award     

Bump-hunting for the proficiency tester--searching for multimodality

Kernel density estimation is a method for producing a smooth density approximation to a dataset and avoiding some of the problems associated with histograms. If it is used with a degree of smoothing determined by a fitness for purpose criterion, it can be applied to proficiency test data in order to test for multimodality in the z-scores. The bootstrap is an essential additional technique to determine how rugged the initially estimated kernel density is: the random resampling of the data in the bootstrap simulates a complete blind repeat of the proficiency test. In addition, useful estimates of the standard error of a mode can be thus obtained. It is suggested that a mode and its standard error can be used as an assigned value and its standard uncertainty.     

A methodology for choosing parameters for ESR readout of alanine dosimeters for radiotherapy

Spectrometer settings for ESR readout of alanine dosimeters for radiotherapy have been investigated. Several ESR parameters were studied and determined. The main reason for this work is to choose the suitable parameters to increase signal-to-noise ratio and to reduce the uncertainty on ESR readout, which is one of the main components of uncertainty of alanine/ESR dosimetry system for radiotherapy. The new spectrometer settings have been applied for ESR readout of alanine dosimeters irradiated from 1 to 10 Gy. A higher signal-to-noise ratio has been achieved compared to our old spectrometer settings. The extended uncertainty (k=2) has been evaluated in the dose range 2–10 Gy (maximum uncertainty of 4.9% for 2 Gy, while minimum uncertainty of 1.4% for 10 Gy), which implies that the alanine/ESR dosimetry system can be applied to radiotherapy dose level that needs a global accuracy of 5%.     

Design for degradation or recycling for reuse?

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Searching for an enhanced predictive tool for mutagenicity

The Multiple Computer Automated Structure Evaluation (MCASE) program was used to evaluate the mutagenic potential of organic compounds. The experimental Ames test mutagenic activities for 2513 chemicals were collected from various literature sources. All chemicals have experimental results in one or more Salmonella tester strains. A general mutagenicity data set and fifteen individual Salmonella test strain data sets were compiled. Analysis of the learning sets by the MCASE program resulted in the derivation of good correlations between chemical structure and mutagenic activity. Significant improvement was obtained as more data was added to the learning databases when compared with the results of our previous reports. Several biophores were identified as being responsible for the mutagenic activity of the majority of active chemicals in each individual mutagenicity module. It was shown that the multiple-database mutagenicity model showed a clear advantage over normally used single-database models. The expertise produced by this analysis can be used to predict the mutagenic potential of new compounds.     

Epidemiological Support for an Hypothesis for Melanoma Induction Indicating a Role for UVA Radiation

An hypothesis for melanoma induction is presented: UV radiation absorbed by melanin in melanocytes generates products that may activate the carcinogenic process. Products formed by UV absorption in the upper layers of the epidermis cannot diffuse down as far as to the melanocytes. Thus, melanin in the upper layer of the skin may be protective, while that in melanocytes may be photocarcinogenic. Observations that support this hypothesis include: (1) Africans with dark skin have a reduced risk of getting all types of skin cancer as compared with Caucasians, but the ratio of their incidence rates of cutaneous malignant melanoma to that of squamous cell carcinoma is larger than the corresponding ratio for Caucasians. (2) Albino Africans, as compared with normally pigmented Africans, seem to have a relatively small risk of getting cutaneous malignant melanomas compared to nonmelanomas. This is probably also true for albino and normally pigmented Caucasians. (3) Among sun-sensitive, poorly tanning persons, frequent UV exposures are associated with increased risk of melanoma, whereas among sun-resistant, well-tanning persons, increased frequency of exposure is associated with decreased melanoma risk. (4) It is likely that UVA, being absorbed by melanin, might have a melanoma-inducing effect. This is in agreement with some epidemiological investigations which indicate that sun-screen lotions may not protect sufficiently against melanoma induction. The relative latitude gradient for UVA is much smaller than that for UVB. The same is true for the relative latitude gradient of cutaneous malignant melanoma as compared with squamous cell carcinoma and basal cell carcinoma. Under the assumption that the average slopes of the curves relating incidence rates with fluences of carcinogenic UV radiation are similar for melanomas and nonmelanomas, these facts are in agreement with the assumption that UVA plays a significant role in the induction of melanomas in humans. This is in agreement with the experimental results with Xiphophorus.