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World Congress on Biosensors 2014

World Congress on Biosensors 2014
Biosensors 2014

Tuesday, 20 March 2012

Just Published: Trends in Analytical Chemistry

A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:

Multidimensional gas chromatography

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34
Philip J. Marriott, Sung-Tong Chin, Bussayarat Maikhunthod, Hans-Georg Schmarr, Stefan Bieri
Analytical multidimensional gas chromatography (MDGC) and the excellent separation efficiency it achieves serve advanced characterization of complex volatile and semi-volatile samples, which is unlikely to be accomplished by single-dimensional chromatography. Here, we provide a technical overview of recent method implementation in MDGC, for both the classical sense (i.e. conventional heart-cut MDGC), including recent approaches to MDGC, and the comprehensive two-dimensional gas chromatography (GC×GC) variant. We summarize selected applications in diverse fields that best typify the role of these methods. We also draw attention to concepts (e.g., orthogonality of separation mechanisms and recently introduced microfluidic technology), and briefly comment on compatibility of detection systems. As a guide to potential opportunities for continued innovation in multidimensional applications, we highlight the capabilities of GC platforms that either combine various GC×GC and MDGC arrangements or offer alternative operational modes for implementation of these methods.

Ambient mass spectrometry for in vivo local analysis and in situ molecular tissue imaging

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34
Peter Nemes, Akos Vertes
Recent technical innovations in mass spectrometry (MS) have extended the application of this powerful technique to direct chemical analysis at atmospheric pressure. These innovations have created an opportunity to appreciate the chemistry of biological systems in their native state, so tissues and single cells of plant, animal, or human origin can be interrogated in situ and in vivo. Ambient MS also allows label-free detection of compounds and gives unique insights into temporal changes and tissue architecture in two and three dimensions. Compounds studied range from natural products (e.g., neurotransmitters, metabolites, organic acids, polyamines, sugars, lipids, and peptides) to xenobiotics (e.g., pharmaceuticals), dyes, polymers, explosives, and toxins. This critical review covers analytical trends in ambient MS. Our discussions primarily touch on the mechanisms of sampling and the bioanalytical implications for in situ and in vivo experiments. We pay special attention to lateral imaging, depth profiling, and three-dimensional-MS imaging, all while working under atmospheric conditions. Our closing remarks highlight some of the present analytical challenges and developmental opportunities in this field.

High-sensitivity analysis of female-steroid hormones in environmental samples

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34
Helena Tomšíková, Jana Aufartová, Petr Solich, Lucie Nováková, Zoraida Sosa-Ferrera, José Juan Santana-Rodríguez
Steroid hormones are endocrine-disrupting compounds, which affect the endocrine system at very low concentrations, so interest in the sensitive determination of steroids in the environment has increased in recent years. In this review, we discuss in detail how to enhance the sensitivity of analytical procedures for the determination of female-steroid hormones (estrogens and progestogens) in environmental matrices. Our objective is to help the reader choose the best analytical tool for sensitive, selective and fast determination of estrogens and progestogens. A number of steps in the analytical procedure, starting with the sample pre-treatment and ending with detection, could significantly contribute to enhancing sensitivity, so they need to be thoroughly optimized. The best results in analysis of estrogens and progestogens have been achieved with liquid chromatography (LC), as separation method, and tandem mass spectrometry (MS), as detection method, but we also discuss analysis using gas chromatography coupled to MS. Sample preparation depends on the kind of sample. Its optimization is important in reducing matrix interferences and plays a significant role in enhancing sensitivity. Liquid samples were most frequently prepared with off-line solid-phase extraction, while solid samples were also extracted by liquid-liquid, pressurized-liquid, microwave and ultrasound extraction techniques. In several studies, derivatization improved the sensitivity of LC-MS detection.

Molecular imprinting for selective chemical sensing of hazardous compounds and drugs of abuse

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34
Piyush Sindhu Sharma, Francis D’Souza, Wlodzimierz Kutner
Environmental and health safety requires thorough determination of hazardous compounds and drugs of abuse. In determinations of these analytes, traditional instrumental analytical techniques often suffer from tedious assay procedures. Biosensors are simpler to construct and faster in use, so they can better meet the analytical demands in determination of these biohazards. However, their stability and reproducibility when operating under harsh conditions are poor, so artificial recognition units have become attractive as replacements for natural receptors in sensing applications. Molecular imprinting is one of the most powerful tools for preparing materials that can bind analytes reversibly and selectively in the presence of their interferents. This review critically evaluates the development of chemical sensing of biohazards and drugs of abuse using the molecular-imprinting approach to recognition in combination with different ways of analytical signal transduction. We compile analytical parameters of the molecularly-imprinted receptors, identify difficulties in the determinations encountered and highlight proposed solutions to problems.

The role of electroanalytical techniques in analysis of polyphenols in wine

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34
Alberto Sánchez Arribas, Marta Martínez-Fernández, Manuel Chicharro
Wine is a major source of polyphenols in the diet, so the characterization and the determination of them in wine samples is a topic of increasing interest with many publications devoted to this issue. Among analytical methods, electroanalytical techniques can obtain valuable information, as the antioxidant activity of polyphenols is related to their electrochemical properties. This review examines the potency of electroanalytical techniques for the direct evaluation of antioxidant activity and total polyphenol content of wines, and the detection and the quantification of individual polyphenols in these samples. We summarize and critically discuss voltammetric approaches using carbon-based and metallic electrodes and biosensors, and their coupling to flow systems (e.g., flow-injection analysis, high-performance liquid chromatography or capillary electrophoresis) with special attention to contributions from 2000 to date.

Analytical techniques for discovery of bioactive compounds from marine fungi

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34
Katia Duarte, Teresa A.P. Rocha-Santos, Ana C. Freitas, Armando C. Duarte
Marine fungi are a promising source of novel bioactive compounds as lead structures for medicine and plant protection. We review current analytical techniques and future perspectives of analytical methodologies from the point of view of the discovery and the characterization of bioactive compounds isolated from marine fungi. This critical overview also includes a general assessment of sampling and preparation of extracts, and compares different methods used for separation and isolation, and different strategies used for structural characterization of the bioactive compounds. We also cover the evolution of the application of bioassays for discovery of bioactive compounds. Finally, this review addresses the advantages and the disadvantages of such techniques, and comments on future applications and potential research interest within this field.

In-line monitoring of chemical-analysis processes using Wireless Sensor Networks

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34
A. Bonastre, J.V. Capella, R. Ors, M. Peris
Wireless Sensor Networks (WSNs) are very promising tools in the advanced automation of chemical-analysis processes. Basically, they are formed by many small devices – called sensor nodes or motes – that can obtain information from the surrounding area using appropriate transducers, and communicate it by suitable wireless-transmission systems. In this article, we study both the application of WSN technology to analytical chemistry and the new research fields for analytical chemistry opened up by the success of WSN applications. A basic “chemical-applied” description of WSNs is followed by the reasons for their implementation and their use in chemical-analysis processes, and comments on the most relevant contributions developed so far. Finally, this article also deals with future trends in this field. Key research challenges to be addressed to deliver remote, wireless, chemosensing systems include the development of low-cost, low-consumption sensors.

Towards greater mechanical, thermal and chemical stability in solid-phase microextraction

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34
Habib Bagheri, Hamed Piri-Moghadam, Mehrnoush Naderi
Solid-phase microextraction (SPME) is a fast, solvent-free technique, which, since its introduction in the 1990s, has been increasingly applied to sample preparation in analytical chemistry. Conventional SPME fibers are fabricated by making a physical bond between the usual silica substrate and the polymeric coatings. However, some applications are limited, as the lifetime and the stability of conventional SPME fibers cannot meet the demands of analyzing relatively non-volatile compounds with more polar moieties. There have been attempts to analyze less volatile compounds by increasing the thermal, physical and chemical stability of the fibers. In this review, we present some new developments in the use of sol-gel technology, molecularly-imprinted polymers (MIPs) and electrochemical deposition to prepare thermally-stable, chemically-bonded, unbreakable SPME fibers.

Recent advances in microemulsion electrokinetic chromatography

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34
Lishuang Yu, Kedan Chu, Hongzhi Ye, Xianxiang Liu, Lishuang Yu, Xueqin Xu, Guonan Chen
Microemulsion electrokinetic chromatography (MEEKC), a special case of electrokinetic chromatography, accomplishes electrokinetic separations using microemulsions as background electrolytes. MEEKC separates solutes based on hydrophobicity and differences in electrophoretic mobility, and it offers highly efficient separation of charged and neutral solutes covering a wide range of water solubility. This review summarizes the development of MEEKC techniques from January 2008 to June 2011. Areas covered include preconcentration techniques, chiral separation, MEEKC coupled to mass spectrometry, and prediction of solute characteristics and partitioning mechanisms. We introduce the fundamentals of MEEKC and discuss recent applications.

Proficiency test in Japan for the elements in tea-leaf powder

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34
Yanbei Zhu, Takayoshi Kuroiwa, Tomohiro Narukawa, Kazumi Inagaki, Koichi Chiba
The National Metrology Institute of Japan (NMIJ) started a series of proficiency test (PT) projects, science 2009, to improve the ability to analyze the elements in environmental and food samples. The first PT was carried out for determination of selected elements (i.e. Al, Ca, Fe, K, P, and Zn) in tea-leaf powder, where a candidate reference material for trace elements in tea-leaf powder was used as the PT material. In the first PT, 41 participants registered, 38 of whom submitted 39 sets of reports. Three national metrology institutes – National Metrology Institute of China, Korea Research Institute of Standards and Science and NMIJ – carried out a co-analysis of the candidate material in parallel with the PT. Certified values, characterized based on independent measurement by NMIJ, were confirmed by the results of co-analysis and were applied as the reference values to evaluate the reported results.

Noticeboard

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry, Volume 34


Sediment and biota in trend monitoring of contaminants in transitional waters

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry
C. Maggi, A. Ausili, R. Boscolo, F. Cacciatore, A. Bonometto, M. Cornello, D. Berto
According to Directive 2008/105/EC, the Italian Parliament issued in 2010 the Legislative Decree 219, which determined the environmental quality standard (EQS) for sediment of marine coastal areas, lagoons and coastal ponds. For the purpose of trend monitoring, sediment and biota are the most suitable matrices for many substances. Directive 2008/105/EC gives an indication of the substances that should be taken into consideration for trend monitoring and sets an integrated water management plan, which has to be prepared for each river-basin district. This article illustrates the criteria that were applied to draw the plan with the aim of assessing the trends of several substances in sediment and biota of the Lagoon of Venice, taking into account the recommendations of Directive 2000/60/EC and the daughter directives. For this purpose, contaminant concentrations coming from a survey conducted in 2005 were compared with the Italian EQS. Results allowed for the evaluation of spatial and temporal trends of several contaminants in sediments and mollusks of the Lagoon of Venice. They allowed us to focus on which compounds need further monitoring and, most of all, which pollutants require measures to reduce inputs.

Biomonitoring of lake sediments using benthic macroinvertebrates

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry
R. Bettinetti, L. Marziali, B. Ponti, B. Rossaro
The Water Framework Directive (2000) is an innovative piece of legislation aimed at protecting the quality of all continental and coastal waters in Europe through an ecological evaluation of the ecosystems. Since it is widely acknowledged that the greater the ecological realism the greater the difficulty of its definition, we describe the different uses of benthic organisms as a tool for assessing the quality of sediment in lakes. We review the responses from single species to the community. Our studies in the laboratory and in the field also critically considered the use of predictive models for these evaluations. Our discussion of the information collected underlines the importance of the relation between sensitivity of single species and contaminants. Moreover, the recent approach in developing mechanistic models to predict the response of natural communities seems to be particularly powerful for community ecology, and we strongly recommend more effort along these lines.

Recent developments in microfluidic devices for in vitro cell culture for cell-biology research

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry
Dan Gao, Hongxia Liu, Yuyang Jiang, Jin-Ming Lin
Microfluidics has developed as a powerful tool for cell-biology research due to its intrinsic advantages. Recently, considerable progress was made in microfluidic technology for cell culture and manipulation, and subsequent treatment and analysis. We summarize microfluidic technologies that improve the efficiency of biological research at the microscale level. From a decade of research, we find that the full integration of microfluidics with cell biology and the development of a microscale cell-culture system show great promise for point-of-care diagnostics and high-throughput drug screening. We discuss recent advances in technologies and methodologies in microfluidic cell culture and their cell-biology applications. We give some insights and directions for researchers interested in developing novel, robust microfluidic platforms for cell-biology research.

Flow-batch analysis

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry
Paulo Henrique Gonçalves Dias Diniz, Luciano Farias de Almeida, David Peter Harding, Mário César Ugulino de Araújo
Since its inception, flow-based analysis has dramatically transformed the way that sample analysis is handled. What used to be manual, slow and prone to error has become automated, rapid and precise. Though many improvements and modifications have already been explored, a most promising development has been the flow-batch analyzer. Through use of an instantaneous stop-mixing chamber and computer-controlled, flow-based sampling, it achieves extraordinarily high sampling rates. We review its historical evolution, components, features and operation, and analytical applications.

Estimation of sampling uncertainty in lake-water monitoring in a collaborative field trial

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry
Fabrizio Botta, Bénédicte Lepot, Eva Leoz-Garziandia, Anne Morin
A collaborative sampling trial was performed by AQUAREF (French national reference laboratory for water and the aquatic environment) at Paladru Lake, Isere, France. This trial was the first national test aiming at improving knowledge of the effect, in lake water, of sampling on global uncertainty. Ten sampling teams regularly involved in Water Framework Directive monitoring of lake water were asked to participate, in agreement with the Regional Water Agencies. All the samples were collected and analyzed by INERIS in order to minimize the analytical impact on global uncertainty. The data treatment was performed according to standard NF ISO 5725-5. Overall results for a few metals (cobalt and nickel) showed predominance (> 90%) of sampling uncertainty compared to analytical uncertainty. For other metals, the initial blank tests showed possible contamination of sampling systems, and really pointed to the importance of blank sampling. Finally, this trial highlighted the need for general guidelines for sampling that could minimize the risk of misclassification of lake-water status.

Quantitative 1H NMR spectroscopy

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry
Santosh Kumar Bharti, Raja Roy
This review illustrates the need to use nuclear magnetic resonance (NMR) spectroscopy for the quantitative analysis of small molecules in their crude forms and in mixtures. We provide the basic concepts of quantitative NMR (qNMR), a brief description of important acquisition and processing parameters responsible for obtaining high-quality, reproducible NMR spectra in order to maximize accuracy, and the latest referencing techniques used for quantitative analysis. We also describe methods that are used for quantitative analysis including calibration-curve and standard-addition methods. Further, we briefly address validation of qNMR spectroscopy and its major applications in various scientific disciplines.

Direct chromatographic methods in the context of green analytical chemistry

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry
Marek Tobiszewski, Jacek Namieśnik
We review analytical protocols based on gas and liquid chromatography (GC and LC), but involving no sample preparation. Green analytical chemistry seeks to minimize negative impacts of analytical chemistry. Direct analytical methods ideally fulfill this requirement, as they preclude sample preparation –the most polluting step of the analytical procedure. We describe examples of GC methodologies for environmental and food analysis using on-column, programmed temperature vaporizers and injectors with sorbent-packed liners. Although LC methods are less amenable to eliminating sample pretreatment, we also present some successful applications of direct LC methods in environmental and food analysis, and bioanalysis.

Multivariate class modeling for the verification of food-authenticity claims

20 March 2012, 09:18:09
Publication year: 2012
Source:TrAC Trends in Analytical Chemistry
Paolo Oliveri, Gerard Downey
Food authenticity is a challenging analytical problem normally addressed using sophisticated laboratory methods that produce large data sets. Multivariate mathematical methods are required to process such data sets, typically to answer a question such as “Is sample X, which claims to be of type A, compatible with type-A samples on the basis of its analytical measurements?”. We recommend class-modeling methods to answer this type of question and discuss the principles, the practice and the results of several types of such methods. We also compare them, in terms of advantages and short-comings, with the discriminant-classification approach. 

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