Comprehensive Two-Dimensional High-Speed Gas Chromatography with Chemometric Analysis

Abstract

High-speed comprehensive two-dimensional gas chromatography (GC×GC) is performed, in which a polar second column performs separations every half second on portions of the effluent from a nonpolar first column. Chemometric techniques that are traditionally used on chromatographic separations with multichannel detection are applied to two-dimensional chromatographic data, for the purpose of quantifying incompletely resolved peaks. Generalized rank annihilation method (GRAM) is evaluated in the quantification of varying amounts of selected overlapped analytes in a GC×GC analysis of modified white gasoline. GRAM requires a sample and standard data set for quantification, and the high retention time precision arising from use of shortened GC columns aids in the analysis. Results from GRAM analysis of GC×GC data are compared with a reference GC method. The test analytes ethylbenzene and m-xylene, existing in various proportions in white gasoline samples, were successfully deconvoluted despite having resolutions of 0.46 and 0.20 on the first and second dimensions of separation, respectively. Like other second-order techniques, GRAM was able to reliably quantify m-xylene despite the presence in the analytical sample of an overlapping compound not present in the calibration standard. Because GRAM can be successfully applied to GC×GC data, full resolution of all the analytes of interest is not necessary. As a result, GC×GC run times can be dramatically shortened, which has significant implications for analyses in which short cycle times are critical, such as in process analysis.

Comprehensive two-dimensional gas chromatography (GC × GC) measurements of volatile organic compounds in the atmosphere

“…Apart from the thermal modulators, valve-based modulators can also be used to make GC×GC measurements (Bruckner et al, 1998;Fraga et al, 2000;Johnson et al, 2002). However, the valve-based modulators send only a part of the effluent from the first column to the second column because they use the so-called heart-cutting technique.…”

Theory and Practice of UHPLC and UHPLC–MS

“…The first attempt in this direction was made by Bruckner et al in 1998, who used four ports (out of six) of a diaphragm valve. The primary column flow was directed to a waste line for most of the modulation period; afterward, the valve was rapidly switched for a brief period, directing the effluent to the second column, pushed by a relatively high auxiliary flow (15 mL/min).…”

Caracterização de amostras petroquímicas e derivados utilizando cromatografia gasosa bidimensional abrangente (GCxGC)

“…Bruckner e colaboradores 21 , em 1998, realizaram uma das primeiras aplicações da GCxGC à análise de gasolina, mas não tiveram por objetivo a separação dos compostos. Amostras de gasolina fortificadas com tolueno, etil-benzeno, m-xileno e propilbenzeno foram utilizadas para demonstrar o uso de análises de segunda ordem dos dados de GCxGC para quantificação de picos sobrepostos, com auxílio de técnicas multivariadas como o Mé-todo Generalizado de Aniquilação de Posto (GRAM, "Generalized Rank Annihilation Method").…”

“…Posteriormente, são referidas as análises de etapas do processamento do petróleo bruto, os avanços nas análises de biomarcadores e, por fim, aplicações envolvendo poluentes ambientais provenientes de petróleo e seus derivados em amostras de ar, água e solo. Dentre as principais aplicações da GCxGC a amostras petroquímicas estão as análises de gasolina 13,14,18,[21][22][23][24][25][26][27][28][29][30] , combustíveis para jatos 22,31 , gasóleo leve 19,32 , óleo diesel 27,[33][34][35][36][37][38] , óleo bruto 20,[39][40][41] , solventes hidrocarbonetos não aromáticos 20 , querosene 15,20,28,32,42,43 , óleos de lavagem 44 , biomarcadores 40,[45][46][47] , poluentes ambientais em ar 10,16,26,34,41,45,[47]…”