Micropreparative system for enrichment of capillary GC effluents

Abstract

SummaryAn automated system for preparative gas chromatography with capillary columns is described. The ellluent from the capillary column is switched to the FID detector or to the traps by means of a Live-T switching device. The pneumatics is controlled by a microprocessor so that repetitive sampling can be performed over a period of days in order to enrich sufficient amounts of material for NMR or other spectroscopic methods. The effluent containing the compounds is collected in glass tubes filled with column packing material (e. g-Chromosorb coated with 3 % OV -101, crosslinked). The trap temperatue can be adjusted from + 20 "C to -80 "C, depending on the trapping material and volatility of trapped substances. The analysis of enriched substances or chromatographic fractions can be performed by thermal desorption of the same traps or by solvent elution. The recovery of enriched substances is higher than 90%. High capacity and resolution for enrichment of trace components are obtained with the aid of a double column-double oven system. Examples of such applications are given.

Review of the role and methodology of high resolution approaches in aroma analysis

“…Enrichment of trace level compounds, particularly for spectroscopic characterisation, is well known, and early applications combining such techniques with good MDGC pre-separation was further proposed by Nitz et al [78] and can be regarded as a technological breakthrough for such applications.…”

Two-Dimensional Gas Chromatography. Concepts, Instrumentation, and Applications - Part 1: Fundamentals, Conventional Two-Dimensional Gas Chromatography, Selected Applications

“…Several heartcuts in close proximity can be isolated from a single run. Potential problems have been reported with the use of Chromosorb based adsorbents [61]. Labile compounds have a tendency to decompose on such surfaces.…”

“…Figure 13.a represents a diagram of a versatile system [61,116]. The instrument incorporates inlets for liquid injection, dynamic headspace enrichment and thermal desorption.…”

“…This methodology may involve dynamic headspace, the use of programmed temperature vaporizers and micro-preparative scale chromatography. Automated systems designed for large scale operation include autosamplers, Two-Dimensional Gas Chromatography and cryogenic traps [61,105,106]. The least complicated approach is the installation of an outlet splitter at the end of the primary column, followed by off-line collection of the desired fraction in an adsorbent trap [107].…”

Selectable one-dimensional or two-dimensional gas chromatography–olfactometry/mass spectrometry with preparative fraction collection for analysis of ultra-trace amounts of odor compounds

“…In the late 80s through early 90s, Nitz et al proposed a modular-type multidimensional (MD) GC system for analysis of odor compounds at low level [2]. For example, they reported 2 D preparative GC [6] in combination with thermal desorption (TD)-GC-O/MS for analysis of passion fruits [7]. After 2 D GC separation and preparative enrichment with an adsorbent trap, the trapped compounds are thermally desorbed and subsequently analyzed by GC-O/MS.…”