Methods in high resolution gas chromatography. Two‐dimensional techniques

Abstract

Basic methodology to effect the separation of complex samples by gas chromatography is discussed from an experimental point of view. Several possibilities are presented which are commonly used to enhance the information content of a gas chromatographic run. These include incorporation of more than one set of retention data, multiple detectors, and special column switching techniques. These and other techniques have sometimes been labeled "multidimensional" in the literature. An attempt is made to define the term "two-dimensional chromatography."The review is divided into sections which point out the different directions which have been taken to deconvolute chromatographically unresolved components. Particular emphasis is placed on technology which is capable of dealing with samples of extreme complexity, and instrumentation for trace-and ultratrace analysis is dicussed with specific examples. The future of two-dimensional techniques in gas chromatography is looked into.

Enantiomeric Composition of Filbertone in Hazelnuts in Relation to Extraction Conditions. Multidimensional Gas Chromatography and Gas Chromatography/Mass Spectrometry in the Single Ion Monitoring Mode of a Natural Sample

“…Techniques such as multidimensional enantioselective gas chromatography (MDGC) (Bertsch, 1978), progress in the development of the derivated cyclodextrins as chiral selector phases (Ko ¨nig, 1992;Schurig and Nowotny, 1988;Weber et al, 1995), and combination of GC and mass spectrometry in the selected ion monitoring [GC/MS(SIM)] represent reliable and powerful methods to avoid peak overlapping and to establish the enantiomeric composition and absolute configurations (Schurig, 1987;Glausch et al, 1995;Blanch et al, 1996).…”

Low cost, robust, in‐house hardware for heart cutting two‐dimensional gas chromatography

“…The present design takes advantage of the development of press-tight connectors [40] to build inert, low volume, zero dead volume sample flow paths. Schomburg et al [29,41] and Bertsch [4] emphasised the need for switching systems to incorporate scavenging gas flows to flush dead volumes in connecting lines and the switch itself, and some switch designs [32,35,36] incorporate bypass (shunt) gas flows to flush connecting lines. Because the present switch design has very short connecting lines (a150 mm from 4-port valve to switch) carrying flows of more than 10 mL/ min through press-fit connectors, fused-silica transfer…”

“…The theoretical expectation that, no matter how long and narrow a capillary column is used, it is practically impossible to resolve every volatile compound in a complex mixture [2] is confirmed empirically by peak overlaps and coelutions when petrochemical or environmental samples, botanical extracts, natural flavours or fragrances, or mammalian semiochemicals are analysed by GC [3][4][5][6][7]. Even a 450 m column with 1.3 million effective plates generated dozens of overlapping peaks from a gasoline standard in a separation that took longer than 11.5 h [8], and resolution among only the C 7 hydrocarbons from crude oil cannot be achieved by any single conventional column [9].…”

Aspects of High-Resolution Gas Chromatography as Applied to the Analysis of Hydrocarbon Fuels and Other Complex Organic Mixtures. Volume 1

“…The theoretical potentials for multidimensional chromatography have been studied [224] and the technology associated with MDGC has been reviewed [225,226]. The extra-column effects in MDGC have been assessed [227], and the effects of pressure and temperature upon solute behavior in coupled column systems have been investigated [228,229], Several studies have been presented which used coupled two-column MDGC systems [230][231][232].…”