A Review of Basic Concepts in Comprehensive Two-Dimensional Gas Chromatography

Ong, Ruby; Marriott, Philip J.

doi:10.1093/chromsci/40.5.276

Cited by 190 publications

(94 citation statements)

References 2 publications

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“…Pulse times must be carefully selected to minimize peak splitting and to optimize transfer to the second column. GC×GC offers enhanced separation efficiency, reliability in qualitative and quantitative analysis, capability to detect low quantities, and information on the whole sample and its components, as recently reviewed (Dallüge et al 2003, Górecki et al 2004, Ong and Marriott 2002.…”

Section: Multidimensional Separationsmentioning

confidence: 99%

Origins of Grape and Wine Aroma. Part 2. Chemical and Sensory Analysis

Robinson

Boss

Solomon

et al. 2014

Am. J. Enol. Vitic.

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Part 1 of this review summarized the current state of knowledge with respect to the chemical compounds contributing to grape and wine aroma. Much of our understanding of the chemistry of grape and wine composition comes from advances in analytical and sensory methods for identifying and quantifying the compounds that contribute to flavor. Therefore, Part 2 of this review provides an overview of the chemical and sensory analysis approaches that have been used to deconstruct wine flavor into its component parts with an aim toward relating the chemical composition to the unique sensory properties that are associated with different wine varieties and styles.Key words: gas chromatography-mass spectrometry, multidimensional separations, sample preparation, sample extraction, GC-olfactometry, sensory descriptive analysis Part 1 of this review provided an overview of the chemical components in grapes and wines and the viticultural, winemaking, and storage practices that influence their formation and concentrations. In Part 2 we provide a summary of the analytical chemistry and sensory approaches for assessing wine flavor. As noted previously, we have attempted to be as complete as possible, however, given the numerous publications in these areas, not all research can be covered (e.g., a Google Scholar search for the phrase "analysis of wine flavor" returns >6,600 publications from the years 2012-2013; the phrase "sensory analysis of wine flavor" returns >5,600 publications over the same period). Therefore, we have chosen to focus on selected recent applications to demonstrate the power and types of information that can be obtained with current analytical and sensory approaches. The reader is also referred to several reviews for more detailed discussions of selected topics (Francis and Newton

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Section: Multidimensional Separationsmentioning

confidence: 99%

Origins of Grape and Wine Aroma. Part 2. Chemical and Sensory Analysis

Robinson

Boss

Solomon

et al. 2014

Am. J. Enol. Vitic.

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“…Using one-dimensional GC-tof-MS, the number of peaks observable in human serum was approximately trebled (compared with another GC-tof-MS method that was the starting point and that we thereby improved) to >1200 [45], which has already enabled the discovery of several novel biomarkers for pre-eclampsia [46] (and see later). Two-dimensional GCxGC-tof-MS has been exploited further to treble this number to >4000 raw peaks, which equates to 1800 metabolite peaks [47,48]. Comparable liquid-phase chromatographies based on reverse-phase UPLC-MS [49,50] can measure thousands of peaks, and a new version of normal-phase UPLC-MS using HILIC [51,52] columns provides complementary measurements.…”

Section: Metabolomics and Technologies For Its Measurementmentioning

confidence: 99%

Systems biology, metabolic modelling and metabolomics in drug discovery and development

Kell

2006

Drug Discovery Today

266

163

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Unlike signalling pathways, metabolic networks are subject to strict stoichiometric constraints. Metabolomics amplifies changes in the proteome, and represents more closely the phenotype of an organism. Recent advances enable the production (and computer-readable encoding as SBML) of metabolic network models reconstructed from genome sequences, as well as experimental measurements of much of the metabolome. There is increasing convergence between the number of human metabolites estimated via genomics ( 3000) and the number measured experimentally. It is thus both timely, and now possible, to bring these two approaches together as an integrated (if distributed) whole to help understand the genesis of metabolic biomarkers, the progress of disease, and the modes of action, efficacy, off-target effects and toxicity of pharmaceutical drugs. Systems biology and metabolic modelling in the 21st CenturyAlthough there are many individual definitions, most commentators (including this one [1,2]) take it that systems biology involves an iterative interplay between more or less high-throughput and high-content 'wet' experiments, technology development, theory and computational modelling, and that it is the involvement of computational modelling, in particular, in the process that sets systems biology apart from the more traditional and more reductionist molecular biology. Metabolomics illustrates this amply. There is also the view that the perceived decrease in the effectiveness of the target-based drug discovery process [3][4][5], including the still-high levels of attrition [6], means that we must move towards understanding organisms at something more akin to a whole-system level [7][8][9][10][11].The question then arises as to what part of a system one might first beneficially model? Although there has, unsurprisingly, been considerable interest in modelling the major signalling pathways (e.g. Refs [12,13]), there are several reasons why it is timely to turn our attention to the level of small molecule metabolism, which is the focus of this review. Metabolism is more discriminatingIt has long been known, and proven through the formalism of metabolic control analysis [7,10,[14][15][16], that whereas small changes in the concentrations of enzymes (and the transcripts that encode them) have only small effects on the fluxes through metabolic pathways, they have substantial effects on the concentrations of metabolic intermediates. Because the metabolome (nominally the concentrations of 'all' the metabolites measured in a system of interest [17]) is downstream of the proteome, it is thereby 'amplified' both in theory [18] and in practice [19,20] and represents a more sensitive level of organisation than do the macromolecular 'omes for understanding a complex biological system, and the changes in it that might be occasioned by disease or pharmaceutical intervention [21,22]. Metabolic reconstruction is now mature and timelyAn attractive feature for the purposes of modelling is that metabolism, in contrast to signalling pathways, ...

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“…A fase de modulação é utilizada para ajustar a posição do máximo do pico relativamente aos eventos de modulação 34 . A Figura 3 apresenta cromatogramas obtidos para os picos modulados de um composto, antes da conversão em diagrama de contorno ou outra representação gráfica.…”

Section: Figura 2 Cromatograma Obtido Por 1d Gc (A) E Diferentes Repunclassified

Nomenclatura na língua portuguesa em cromatografia multidimensional abrangente

et al. 2007

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Recebido em 26/10/05; aceito em 14/9/06; publicado na web em 7/2/07 NOMENCLATURE FOR COMPREHENSIVE MULTIDIMENSIONAL CHROMATOGRAPHY IN PORTUGUESE LANGUAGE. Comprehensive Multidimensional Chromatography is a relatively new analytic technique, which is receiving growing attention in many parts of the world, including recently in Brazil. This work presents terms in Portuguese which are commonly used in Comprehensive Multidimensional Chromatography in order to help standardize the vocabulary employed in this area in the scientific literature. It also includes some symbols, their nominations, and explanation of some terms, whenever necessary. This proposal does not intend to be comprehensive or definitive; on the contrary, it intends to be a first step in the process of establishing a standardized nomenclature, serving as a base for a further sound discussion in the scientific community realm.Keywords: comprehensive multidimensional chromatography; nomenclature; comprehensive two dimensional gas chromatography. INTRODUÇÃOO uso de termos, abreviações e símbolos em áreas novas do conhecimento científico pode conduzir à propagação de uma grande variedade de expressões, muitas delas inadequadas, dificultando a comunicação entre os integrantes da comunidade científica e demais profissionais da área, como também a compreensão dos fenômenos científicos envolvidos. A cromatografia multidimensional abrangente é uma área relativamente nova dentre as técnicas de separação, a qual tem experimentado rápido desenvolvimento em várias partes do mundo e que apresenta também no Brasil excelentes perspectivas de crescimento 1 . Para que uma técnica cromatográfica multidimensional seja considerada abrangente, todo o efluente da primeira dimensão, ou uma parte suficientemente representativa do mesmo, deverá ser introduzida na segunda dimensão, mantendo as características da separação ocorrida na primeira dimensão 2,3 . Se apenas algumas regiões da primeira dimensão forem introduzidas na segunda, a técnica será multidimensional, mas não abrangente. Na cromatografia gasosa bidimensional (GC-GC) e na cromatografia líquida bidimensional (LC-LC) do tipo "heart-cut", pequenas frações do efluente da primeira coluna são transferidas para uma segunda coluna, onde a seletividade diferenciada desta segunda coluna fornece um aumento da resolução dos picos cromatográficos da zona de "heart-cut". Entretanto, apenas algumas regiões da primeira dimensão são transferidas para a segunda, sendo portanto, uma técnica não abrangente 4 . A cromatografia multidimensional abrangente é também caracterizada pela utilização seqüencial de duas colunas, uma com dimensões convencionais e a outra mais curta (do tipo de coluna usada em cromatografia rápida), havendo um modulador entre elas. As colunas devem ter fases estacionárias diferentes, permitindo que a separação pouco eficiente, obtida na primeira coluna, seja melhorada na segunda. O sistema de modulação entre as duas colunas causa uma compressão da banda cromatográfica que elui da primeira coluna, sendo esta ban...

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A Review of Basic Concepts in Comprehensive Two-Dimensional Gas Chromatography

Cited by 190 publications

References 2 publications

Origins of Grape and Wine Aroma. Part 2. Chemical and Sensory Analysis

Origins of Grape and Wine Aroma. Part 2. Chemical and Sensory Analysis

Systems biology, metabolic modelling and metabolomics in drug discovery and development

Nomenclatura na língua portuguesa em cromatografia multidimensional abrangente

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