Article

# Simple, non-moving modulation interface for comprehensive two-dimensional gas chromatography

Department of Analytical Chemistry and Applied Spectroscopy, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, Netherlands
(Impact Factor: 4.26). 07/2001; 919(1):127-132. DOI: 10.1016/S0021-9673(01)00785-3

ABSTRACT A simple, non-moving dual-stage CO2 jet modulator is described, which cools two short sections of the front end of the second-dimension column of a comprehensive two-dimensional gas chromatograph. A stream of expanding CO2 is sprayed directly onto this capillary column to trap small fractions eluting from the first-dimension column. Remobilization of the trapped analytes is performed by direct heating by the GC oven air. Installation, maintenance and control of the modulator is simple. Focusing and remobilization of the fractions is a very efficient process, as the bandwidths of the re-injected pulses are less than 10 ms. As a result, alkane peaks eluting from the second-dimension column have peakwidths at the baseline of only 120 ms.

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Available from: René Vreuls, Jun 16, 2014
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• "The LMCS (Longitudinally Modulation Cryogenic System) generates modulation by moving back and forth a cryogenic CO 2 spray along the head of the second column (Marriott and Kinghorn, 1997; Kinghorn and Marriott, 2000). The dual-jets CO 2 modulator enables modulation by turning on and off two sprays of CO 2 applied on the column (Beens et al., 2001). The cryogenic approach is devoted to a wider boiling point range of volatile compounds but liquid nitrogen should be preferred to CO 2 for trapping of very volatile solutes. "
##### Article: Comprehensive Two-Dimensional Gas Chromatography for Detailed Characterisation of Petroleum Products
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ABSTRACT: Comprehensive Two-Dimensional Gas Chromatography for Detailed Characterisation of Petroleum Products — Comprehensive two-dimensional gas chromatography (GC×GC) is a major advance for the detailed characterisation of petroleum products. This technique is based on two orthogonal dimensions of separation achieved by two chromatographic capillary columns of different chemistries and selectivities. High-frequency sampling between the two columns is achieved by a modulator, ensuring that the whole sample is transferred and analysed continuously in both separations. Thus, the peak capacity and the resoluting power dramatically increase. Besides, highly structured 2D chromatograms are obtained upon the volatility and the polarity of the solute to provide more accurate molecular identification of hydrocarbons. In this paper fundamental and practical considerations for implementation of GC×GC are reviewed. Selected applications obtained using a prototype of a GC×GC chromatograph developed in-house highlight the potential of the technique for molecular characterisation of middle distillates, sulphur speciation in diesel and analysis of effluents from petrochemical processes.
Oil & Gas Science and Technology 01/2007; 62(1). DOI:10.2516/ogst:2007004 · 1.11 Impact Factor
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• "GC3GC: a revolutionary development A very simple and revolutionary innovation in GC is socalled 'GC3GC' or 'comprehensive 2-dimensional GC' in which a non-polar column can be coupled to a shorter polar column. The temperature of the junction between the columns is modulated by a moving heater (Kinghorn and Marriott, 1998a) or jets of gas (Ledford and Billesbach, 2000; Beens et al., 2001) so that peaks from the first column are continually 'frozen' (modulated) and transferred to the second, faster-running column. If the first column can separate 300 peaks and the second column 15 peaks, the total resolving power of the system is 300315=4500 peaks, representing a staggering increase in analytical power! "
##### Article: Chemical derivatization and mass spectral libraries in metabolic profiling by GC/MS and LC/MS/MS
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ABSTRACT: An overview is presented of gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS), the two major hyphenated techniques employed in metabolic profiling that complement direct ‘fingerprinting’ methods such as atmospheric pressure ionization (API) quadrupole time-of-flight MS, API Fourier transform MS, and NMR. In GC/MS, the analytes are normally derivatized prior to analysis in order to reduce their polarity and facilitate chromatographic separation. The electron ionization mass spectra obtained are reproducible and suitable for library matching, mass spectral collections being readily available. In LC/MS, derivatization and library matching are at an early stage of development and mini-reviews are provided. Chemical derivatization can dramatically increase the sensitivity and specificity of LC/MS methods for less polar compounds and provides additional structural information. The potential of derivatization for metabolic profiling in LC/MS is demonstrated by the enhanced analysis of plant extracts, including the potential to measure volatile acids such as formic acid, difficult to achieve by GC/MS. The important role of mass spectral library creation and usage in these techniques is discussed and illustrated by examples.
Journal of Experimental Botany 02/2005; 56(410):219-43. DOI:10.1093/jxb/eri069 · 5.79 Impact Factor
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• "The LMCS (Longitudinally Modulation Cryogenic System) generates modulation by moving back and forth a cryogenic CO 2 spray along the head of the second column (Marriott and Kinghorn, 1997; Kinghorn and Marriott, 2000). The dual-jets CO 2 modulator enables modulation by turning on and off two sprays of CO 2 applied on the column (Beens et al., 2001). The cryogenic approach is devoted to a wider boiling point range of volatile compounds but liquid nitrogen should be preferred to CO 2 for trapping of very volatile solutes. "
##### Article: Chromatographie en phase gazeuse bidimensionnelle pour l'analyse détaillée des produits pétroliers
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ABSTRACT: Comprehensive two-dimensional gas chromatography (GC$\times$GC) is a major advance for the detailed characterisation of petroleum products. This technique is based on two orthogonal dimensions of separation achieved by two chromatographic capillary columns of different chemistries and selectivities. High-frequency sampling between the two columns is achieved by a modulator, ensuring that the whole sample is transferred and analysed continuously in both separations. Thus, the peak capacity and the resoluting power dramatically increase. Besides, highly structured 2D chromatograms are obtained upon the volatility and the polarity of the solute to provide more accurate molecular identification of hydrocarbons. In this paper fundamental and practical considerations for implementation of GC$\times$GC are reviewed. Selected applications obtained using a prototype of a GC$\times$GC chromatograph developed in-house highlight the potential of the technique for molecular characterisation of middle distillates, sulphur speciation in diesel and analysis of effluents from petrochemical processes. La chromatographie gazeuse bidimensionnelle intégrale (CG$\times$CG) représente une avancée majeure pour l'analyse détaillée des produits pétroliers. Cette technique est fondée sur deux dimensions orthogonales que forme l'association de deux colonnes de CG de sélectivités de séparation différentes. L'échantillonnage à haute fréquence à l'interface des deux colonnes permet que la totalité du produit soit transférée et analysée dans les deux dimensions. Ainsi, la capacité de pics et le pouvoirrésolutif sont nettement accrus. En outre, les chromatogrammes 2D sont structurés en fonction des propriétés de volatilité et de polarité des hydrocarbures ce qui facilite leur identification. Dans cet article sont présentés les concepts et le principe de mise en œuvre de la CG$\times$CG. Un système prototype a été développé à l'IFP comprenant notamment un modulateur à double-jets de CO$_2$ et un logiciel de posttraitement pour la visualisation et l'intégration des chromatogrammes. Les exemples d'application choisis illustrent le potentiel de la technique pour la caractérisation détaillée de distillats moyens, la spéciation de composés soufrés dans les gazoles et l'analyse approfondie des effluents de procédés pétrochimiques.