Compehensive two‐dimensional gas chromatography (GC×GC) and its applicability to the characterization of complex (petrochemical) mixtures

Abstract

In general, petrochemical products contain only a limited number of chemical classes of compounds (sample dimensionality). The enormous number of individual components within these classes, however, soon puts limitations upon a single chromatographic technique when it comes to adequate characterization of these products. Comprehensive two‐dimensional gas chromatography (GC×GC) clearly opens the possibility of estimating the composition of hydrocarbon mixtures in a far more detailed fashion than hitherto possible. Although the emphasis of papers of GCxGC thus far almost exclusively applies to the unsurpassed peak‐capacity, in the oil industry there is a need for characterization, rather than for analyzing all the individual compounds. In principle a GCxGC system can provide an almost perfect match between its intrinsic properties and the dimensionality of oil samples. To establish the applicability of GCxGC towards petrochemical analytical challenges, a commercially aavailable prototype instrument was subjected to an exhaustive characterization of a typical hydrocarbon precess stream and a fast characterization of a light gas oil. Although there are no fundamental limitations towards the quantitative aspects of a GCxGC system, this paper confines itself to qualitative results only. Quantitative aspects of GCxGC will be published in a forthcoming paper.

Advances and Changes in the Techniques of Multi- Dimensional and Comprehensive Chromatography and When Coupled with Mass Spectrometry

“…Murphy et al [7] have considered a theoretical criterion for realizing the ideal 2D peak capacity which provides information as to how often the 1D effluent must be sampled so that the resolution gained in the 1D is not partially lost due to the sampling process, which is required to carry out separation effectively in the second dimension. Essentially the effluent must be sampled at least three to four over 8σ width of a 1D peak to avoid significant loss of 2D resolution between a pair of peaks when the 1D separation contributes significantly to the overall resolution (M-S-F sampling criterion).…”

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

“…Blomberg e colaboradores 19 utilizaram a GCxGC-FID com modulador de rotação térmica para caracterização exaustiva de um corte da destilação (150-400 o C) de um Ciclo de Craqueamento Catalítico de um Óleo Pesado (HCCCO -"Heavy Catalytic Cracked Cycle Oil") e de seus produtos de hidrogenação. Vários compostos foram identificados nestas amostras, sendo eles saturados, mono-, di-, tri-aromáticos e compostos sulfurados.…”

“…O número de compostos, somente no destilado intermediário, foi estimado acima de um milhão 19 . Por este motivo, é praticamente impossível realizar uma caracterização cromatográfica de todos os compostos de uma amostra de petróleo bruto em uma única separação cromatográfica, fazendo-se, portanto, apenas a identificação dos compostos por classes químicas.…”

“…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]…”

Two-dimensional gas chromatography-online hydrogenation for improved characterization of petrochemical samples

“…The application of GC×GC to the analysis of highly complex petrochemical mixtures has been described by a number of authors [3][4][5][6][7][8][9]. However, despite the increase in separation power, peak co-elution still occurs when samples containing isomeric compounds are 3 analysed by comprehensive two dimensional GC.…”