CE microchips: an opened gate to food analysis

CE microchips are the first generation of micrototal analysis systems (-TAS) emerging in the miniaturization scene of food analysis. CE microchips for food analysis are fabricated in both glass and polymer materials, such as PDMS and poly(methyl methacrylate) (PMMA), and use simple layouts of simple and double T crosses. Nowadays, the detection route preferred is electrochemical in both, amperometry and conductivity modes, using end-channel and contactless configurations, respectively. Food applications using CE microchips are now emerging since food samples present complex matrices, the selectivity being a very important challenge because the total integration of analytical steps into microchip format is very difficult. As a consequence, the first contributions that have recently appeared in the relevant literature are based primarily on fast separations of analytes of high food significance. These protocols are combined with different strategies to achieve selectivity using a suitable nonextensive sample preparation and/or strategically choosing detection routes. Polyphenolic compounds, amino acids, preservatives, and organic and inorganic ions have been studied using CE microchips. Thus, new and exciting future expectations arise in the domain of food analysis. However, several drawbacks could easily be found and assumed within the miniaturization map.     

微流控芯片在食品安全分析中的应用进展

微流控芯片技术可以实现从样品处理到检测的微型化、自动化、集成化及便携化,因而在食品安全检测方面展现出强大的发展活力。目前微流控芯片技术在农药残留、兽药残留、重金属、食品添加剂等食品安全检测方面已取得了一系列重要进展。该文着重介绍了微流控芯片技术在食品安全分析中的研究进展,并展望了其在食品安全分析中的应用前景。     

Direct Electrochemical Sensing and Detection of Natural Antioxidants and Antioxidant Capacity in Vitro Systems

This review highlights the role of electrochemical approaches in the sensing of antioxidants and their antioxidant capacity with especial attention to the analytical possibilities of electrochemistry in the direct evaluation of antioxidant capacity exhibited by food and biological samples due to the termed dietary, natural or biological antioxidants (mainly polyphenols, and vitamins C and E). The analytical potency of the electrochemistry is comprehensively stated and the selected results found in the literature are summarized and discussed critically. The main electrochemical approaches used have been cyclic voltammetry (CV) and flow injection analysis with amperometric detection (FIA‐ED). In addition, miniaturization is going to break new frontiers in the evaluation of antioxidant activity.     

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。     

Electrochemical enzyme immunoassay using model labels

Enzyme immunoassays (EIAs) based on electrochemical detection offer several potential advantages and have been applied in clinical, medical, biotechnological, food and environmental analysis. Among the enzyme labels employed, horseradish peroxidase (HRP), alkaline phosphatase (ALP) and glucose oxidase (GOx) are the most common. This brief review reflects recent advances, challenges, and trends of electrochemical EIAs focusing on HRP, ALP or GOx as labels over the past five years. We especially emphasize current development of EIAs combined with other developments, including nanotechnology and miniaturization.     

Miniaturized sample preparation and separation methods for environmental and drug analyses.

Miniaturized extraction and separation media have been successfully developed from precisely controlled technologies. In this article, recent developments in these high performance analytical methods, such as miniaturized sample preparation methods and the coupling of these techniques with microscale separation systems, have been reviewed, along with some applications to environmental and biological analysis. The advantage of the miniaturization is not only for the environmental compatibility but also for the developments of the high performance analytical systems. Down-sizing also makes it possible to investigate and introduce various compounds and materials as novel media (such as tailor-made materials and devices) in separation science. As a typical example of the novel miniaturized sample preparation system, the applications of fibrous materials for microcolumn liquid-phase separation methods are described.     

毛细管电泳分析中的富集技术及其应用

毛细管电泳（CE）具有分析速度快、分离效率高、样品消耗少、成本低廉等优点,已被应用于无机离子、有机小分子、蛋白质、核酸及细胞等的分析中。CE中最常用的检测方式是紫外检测（UV）,但由于常规进样样品体积小、检测光程短,CE-UV的灵敏度往往不能满足复杂样品中痕量物质直接分析的要求。CE中的在柱富集技术包括堆积、动态pH界面、吹扫和瞬间等速电泳等,可在很大程度上提高CE-UV的检测灵敏度;另外,固相和液相微萃取技术及其与在柱富集技术相结合应用在CE中也能净化样品基质,进一步提高富集倍数,改善分析灵敏度,从而拓宽了CE-UV在复杂样品分析中的应用范围。     

Diiron-containing metalloproteins: Developing functional models

A major objective in protein science is the design of enzymes with novel catalytic activities that are tailored to specific applications. Such enzymes may have great potential in biocatalysis and biosensor technology, such as in degradation of pollutants and biomass, and in drug and food processing. To reach this objective, investigations into the basic biochemical functioning of metalloproteins are still required. In this perspective, metalloprotein design provides a powerful approach first to contribute to a more comprehensive understanding of the way metalloproteins function in biology, with the ultimate goal of developing novel biocatalysts and sensing devices. Metalloprotein mimetics have been developed through the introduction of novel metal-binding sites into naturally occurring proteins as well as through de novo protein design. We have approached the challenge of reproducing metalloprotein active sites by using a miniaturization process. We centered our attention on iron-containing proteins, and we developed models for heme proteins and diiron–oxo proteins. In this paper we summarize the results we obtained on the design, structural, and functional properties of DFs, a family of artificial diiron proteins.     

微流控芯片技术及在药物分析中的应用研究进展

微流控芯片由于具有试剂和样品用量少、分析速度快、分离效率高、体积小等优点,近几年发展迅速,已应用于医药、化学和生物等领域.本文就微流控芯片的最新研究进展以及它在药物分析中的应用作简要的综述.引用参考文献58篇.     

Modern automated microextraction procedures for bioanalytical,environmental, and food analyses

Sample preparation frequently is considered the most critical stage of the analytical workflow. It affects the analytical throughput and costs; moreover, it is the primary source of error and possible sample contamination. To increase efficiency, productivity, and reliability, while minimizing costs and environmental impacts, miniaturization and automation of sample preparation are necessary. Nowadays, several types of liquid-phase and solid-phase microextractions are available, as well as different automatization strategies. Thus, this review summarizes recent developments in automated microextractions coupled with liquid chromatography, from 2016 to 2022. Therefore, outstanding technologies and their main outcomes, as well as miniaturization and automation of sample preparation, are critically analyzed. Focus is given to main microextraction automation strategies, such as flow techniques, robotic systems, and column-switching approaches, reviewing their applications to the determination of small organic molecules in biological, environmental, and food/beverage samples.     

Monolith as a new sample preparation material: recent devices and applications

Monolith was first used as a material for chromatographic separation two decades ago and solid-phase extraction over 10 years, and since then, separation science has undergone a dramatic change owing to advancements in analytical technology. Recently, monolith has been modified to suit various devices for the extraction and enrichment of analytes in any matrices of environmental, food, and biological analyses. This approach has contributed to miniaturization and automation for sample preparation, and it can reduce the time and cost requirements of sample preparation. Recently, numerous applications have been demonstrated for online and inline preconcentration coupled with monolith, and many kinds of devices have been designed and developed for offline devices. In this review, these applications and devices are listed and discussed in reference to other fields.     

Recent advances and trends in miniaturized sample preparation techniques

Advances in the area of sample preparation are significant and have been growing significantly in recent years. This initial step of the analysis is essential and must be carried out properly, consisting of a complicated procedure with multiple stages. Consequently, it corresponds to a potential source of errors and will determine, at the end of the process, either a satisfactory result or a fail. One of the advances in this field includes the miniaturization of extraction techniques based on the conventional sample preparation procedures such as liquid‐liquid extraction and solid‐phase extraction. These modern techniques have gained prominence in the face of traditional methods since they minimize the consumption of organic solvents and the sample volume. As another feature, it is possible to reuse the sorbents, and its coupling to chromatographic systems might be automated. The review will emphasize the main techniques based on liquid‐phase microextraction, as well as those based upon the use of sorbents. The first group includes currently popular techniques such as single drop microextraction, hollow fiber liquid‐phase microextraction, and dispersive liquid‐liquid microextraction. In the second group, solid‐phase microextraction techniques such as in‐tube solid‐phase microextraction, stir bar sorptive extraction, dispersive solid‐phase extraction, dispersive micro solid‐phase microextraction, and microextraction by packed sorbent are highlighted. These approaches, in common, aim the determination of analytes at low concentrations in complex matrices. This article describes some characteristics, recent advances, and trends on miniaturized sample preparation techniques, as well as their current applications in food, environmental, and bioanalysis fields.     

Ultramicroextraction as a miniaturization of the already miniaturized. A step toward nanoextraction and beyond

Miniaturization of the analytical process has been a widespread trend, and the sample preparation stage is not exempted from this downscaling. Since the introduction of microextraction techniques as miniaturization of classical extraction techniques, they have become one of the strengths in this field. However, some of the original approaches to these techniques did not fully cover all the current principles of Green Analytical Chemistry. For this reason, during the last years, much emphasis has been placed on reducing/eliminating toxic reagents, reducing the amount of the extraction phase, and searching for new greener, and more selective extractant materials. On the other hand, even though high accomplishments have been achieved, the same attention has not always been paid to reducing the amount of sample, which is essential when treating low-availability samples such as biological samples, or in developing portable devices. In this review, we intend to give the readership an overview of the advances toward further miniaturization of microextraction techniques. Finally, a brief reflection is made on the terminology used, or that should, in our opinion, be used to term these new generation of miniaturized microextraction approaches. To this regard, the term, ‘ultramicroextraction’ is proposed to refer to those approaches beyond microextraction.     

Recent advances in miniaturization of portable liquid chromatography with emphasis on detection

Liquid chromatography is a prominent analytical technique in separation science and chemical analysis, applied across numerous fields of research and within industrial applications. Over the past few decades, there has been a growing interest in the miniaturization of this technique, which has been particularly enabled through new miniature and portable detection technologies for in-field, at-site, and point-of-need (collectively ‘out-of-lab’) analyses. Accordingly, significant advances have been made in recent years in the development of miniaturized liquid chromatography with photometric, electrochemical, and mass spectrometric detection, enabling the development of field-deployable and portable instruments for various applications. Herein, recent developments in the miniaturization of detection systems for inclusion within, and/or coupling with, portable liquid chromatographic systems, are reviewed in detail together with critical comments and expected future trends in this area.     

微流控技术在生命分析化学中的应用进展

微流控分析系统与宏观条件下的分析体系相比,具有样品和试剂消耗小、传质传热效率高、生物相容性较好、高通量并行分析、功能单元集成化、微型化及自动化控制等特点,在分析化学尤其是生命分析化学领域得到了广泛应用。本文以涉及细胞的微流控技术为切入点,主要介绍了近五年来微流控芯片相关技术的发展,如芯片材料与制作技术、表面改性技术和液滴技术等,并简单总结微流控技术在药物筛选和细胞分析等生命分析化学领域的研究应用进展。     

Enantioseparation/Recognition based on nano techniques/materials

Enantiomers show different behaviors in interaction with the chiral environment. Due to their identical chemical structure and their wide application in various industries, such as agriculture, medicine, pesticide, food, and so forth, their separation is of great importance. Today, the term “nano” is frequently encountered in all fields. Technology and measuring devices are moving towards miniaturization, and the usage of nanomaterials in all sectors is expanding substantially. Given that scientists have recently attempted to apply miniaturized techniques known as nano-liquid chromatography/capillary-liquid chromatography, which were originally accomplished in 1988, as well as the widespread usage of nanomaterials for chiral resolution (back in 1989), this comprehensive study was developed. Searching the terms “nano” and “enantiomer separation” on scientific websites such as Scopus, Google Scholar, and Web of Science yields articles that either use miniaturized instruments or apply nanomaterials as chiral selectors with a variety of chemical and electrochemical detection techniques, which are discussed in this article.     

Study of the migration of additives from plasticized PVC

The aim of this paper is to study the interactions between packaging and food. For that purpose, additives were first characterized. Kinetic studies of their specific migrations have been carried out by using different analytical methods such as gas chromatography, Fourier transform infrared spectroscopy, atomic absorption spectrometry and differential scanning calorimetric analysis. The influence of various parameters such as temperature, agitation, nature of food simulant and initial concentration of plasticizer was considered.     

Electroanalytical methods based on bimetallic nanomaterials for determination of pesticides: Past,present, and future

The excessive use of pesticides in agricultural or non-agricultural fields causes the emergence of environmental and human health problems. Therefore, there is a need to develop simple, fast, sensitive, selective, and low-cost methods for analyzing pesticides from different matrices. Although many analysis methods have been developed to determine pesticides, nanomaterial-based electroanalytical methods offer numerous advantages such as rapid and low cost of analysis, low sample volume requirement, field deployability, and miniaturization to improve the performance of the developed methods. Among different nanomaterials, bimetallic nanomaterials such as gold, platinum, palladium, nickel, and iron-based nanomaterials in combination with other metals have been extensively used as electrode modification agents due to their electrocatalytic characteristics and the synergistic effect of two metals. In this review, firstly, the basic information of pesticides and bimetallic nanomaterials was summarized. Properties, synthesize, and architectures of bimetallic nanomaterials and their nanocomposites were explained in detail. Current applications and utilization of bimetallic nanomaterials for pesticides detection were reviewed by selected studies with working range, the limit of detection, sensitivity, analytical application, and some experimental conditions. In conclusion, the current challenges and future trends for analyzing pesticides based on electroanalytical methods combined with bimetallic nanomaterials were highlighted.     

Fully integrated microfluidic separations systems for biochemical analysis

Over the past decade a tremendous amount of research has been performed using microfluidic analytical devices to detect over 200 different chemical species. Most of this work has involved substantial integration of fluid manipulation components such as separation channels, valves, and filters. This level of integration has enabled complex sample processing on miniscule sample volumes. Such devices have also demonstrated high throughput, sensitivity, and separation performance. Although the miniaturization of fluidics has been highly valuable, these devices typically rely on conventional ancillary equipment such as power supplies, detection systems, and pumps for operation. This auxiliary equipment prevents the full realization of a "lab-on-a-chip" device with complete portability, autonomous operation, and low cost. Integration and/or miniaturization of ancillary components would dramatically increase the capability and impact of microfluidic separations systems. This review describes recent efforts to incorporate auxiliary equipment either as miniaturized plug-in modules or directly fabricated into the microfluidic device.     

酶生物燃料电池自供能传感器的研究现状及应用

在现代分析领域中,对于生物传感器的要求不断倾向于微型化和便捷化。基于酶型生物燃料电池的自供能传感器在检测目标物的同时可以提供能量,避免了外电源的使用,为生物传感器的微型化和便捷化发展提供了有效途径,日益成为人们关注的焦点。本文按照设计原理进行分类,对近五年内发展的基于酶型生物燃料电池的自供能传感器进行了综述,并展望了其今后的研究趋势和应用前景。