Selective and non‐selective sampling from precolumn separations—with emphasis on the sampling of aqueous solutions

Abstract

Various methods of gas chromatographic analysis at high resolution and low detection limits in aqueous solutions are described with regard to sampling techniques, column technology, and the application of coupled pre-columns, also including multidimensional methods. Immobilized polyethylene glycol (Carbowax 20 M) columns have also been produced and used successfully.

Trace level analysis of micropollutants in aqueous samples using gas chromatography with on-line sample enrichment and large volume injection

“…Most of the problems associated with direct introduction of water samples can be solved by using two-dimensional GC systems, as was already shown several years ago [59]. Up to 200/LI of water sample could be injected onto a Tenaxpacked GC column at a temperature above the solvent boiling point, the water bei~lg eluted while the analytes (cresols/alcohols) were retained.…”

Programmed‐temperature injector for large‐volume sample introduction in capillary gas chromatography and for liquid chromatography‐gas chromatography interfacing

“…To facilitate the solvent evaporation process and to obtain narrow input bands for the solutes in the analytical column, many different techniques have been proposed: retention gap techniques [20-231, concurrent solvent evaporation [20,24], programmed-temperature vaporizer (PTV) injections [25,26], injections on a packed precolumn [27,28], a specially designed device incorporating a 500 pL reservoir [29], and selective solute trapping from vaporized samples [30]. Currently, the first two techniques (i.e., retention gap techniques and concurrent solvent evaporation) are used for solvent removal in coupled LC-GC.…”

Analysis of trace oxygenated hydrocarbons in the environment

“…However, the two-dimensional gas chromatographic analytical method (Berg and Jonsson, 1984) was extremely helpful, because it used the same general approach as other laboratories (Miller et al, 1979;Schomburg et al, 1984), whose methods we had been considering. Since the Jonsson and Berg method had proved successful, we borrowed several elements from it, modifying them to fit our equipment (a Hewlett-Packard 5890 GC equipped with FID and PID detectors, a Tekmar Model 1000 cryogenic-focusing capillary interface, and a Valco 6-port capillary switching valve), and our sampling method, which uses direct cryogenic trapping of samples in a flow-through system immersed in liquid nitrogen (LN 2 , or liquid argon (LAr, -185 °C).…”