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

Abstract

The introduction of large sample volumes in capillary gas chromatography is becoming increasingly important in various application areas. Especially in the analysis of very dilute sample (e.g., environmental samples) and in coupled LC‐GC, large volume sampling is extremely important. Programmed‐temperature sample introduction is shown to be an attractive technique for these purposes. In this paper we present some applications of large volume sampling in environmental analysis. Water samples were analyzed using both off‐line and on‐line extraction with gas chromatography (GC) analysis. In the off‐line method, pollutants were extracted into hexane or methylene chloride. Using the programmed‐temperature injector, up to 250 μL of the extract could be introduced into the GC system. In this way, reproducible quantitative analysis of PAHs and herbicides were achieved at sub‐ppb concentrations using flame ionization detection. In the on‐line mode, pollutants were preconcentrated on a short liquid chromatography (LC) column packed with a PLRP‐S solid phase extraction material. After the trapping step, the components were desorbed by ethyl acetate and transferred directly into the programmed‐temperature vaporizer (PTV‐GC) system. Using this method, detection limits below about 1 ppb of herbicides in water were obtained.

Coupled High Performance Liquid Chromatography with High Resolution Gas Chromatography

“…The introduction of large volumes with the use of such an injector in solvent-split mode was first investigated in the 1970s. Staniewski, Cramers and co-workers (12)(13)(14)(15)(16)(17) demonstrated that by reducing the injector temperature and by increasing the purge gas during the solvent elimination it was easier to remove solvent, and showed that by using chambers packed with porous glass beads instead of Tenax TA or Thermotrap recovery of solutes may be improved.…”

Determination of triazine herbicides by capillary gas chromatography with large-volume on-column injection

“…[9] or by off-line or on-line extraction coupled to gas chromatography [10]; the latter technique was applied to the determination of PAHs and herbicides in water samples.…”

“…Different approaches are available for achieving largevolume injection in capillary gas chromatography: oncolumn injection [1][2][3][4][5][6], programmed-temperaturevaporization injection [7][8][9][10] or splitless injection with solvent diversion [11,12]. Although the use of largevolume injection in GC has been described in several papers, few references deal with the determination of pesticides in environmental samples.…”

Rapid screening of volatile compounds in edible plants by direct chromatographic analysis

“…The elimination of the solvent and the gas chromatographic analysis of the thermally desorbed compounds is subsequently performed. Specifically, the optimisation of a number of variables involved in the retention of the target solutes in an adsorbent kept inside the PTV injector body has allowed the determination of trace compounds in very different matrices (Mol, Janssen, Cramers, Vreuls, & Brinkman, 1995;Staniewski, Janssen, Cramers, & Rijks, 1992;Villén, Señoráns, Reglero, & Herraiz, 1995, 1996.…”