Volatile oil analysis of Thymus vulgaris L. by directly coupled SFE/GC

Abstract

Abstract. Dynamic supercritical fluid extraction (SFE) with CO, as the supercritical fluid was coupled to capillary gas chromatography (GC). A cryotrap/thermal desorption unit external to the GC was used to collect the extracted compounds and introduce them into the GC column. The reproducibility of the SFE/GC system was tested through replicate analyses of thyme, and the recoveries of thyme components were compared with those obtained from hydrodistilled oil of thyme by GC. Excellent agreement was achieved, but the results showed that chromatographic valves and valve materials may be critical in obtaining good results.

Carvone and limonene in caraway fruits (Carum carvi L.) analyzed by supercritical carbon dioxide extraction-gas chromatography

“…The solutes were purged and focused with supercritical fluid onto the capillary GC column, whereby only a part of the carbon dioxide flow passed through the analytical column and better peak shape was obtained. Ashraf-Khorassani et al ( ), Cotton et al (1991, and Hartonen et al (1992) used various cryogenic collection systems, which were effective in trapping volatile substances.…”

“…Instrumentation of directly coupled SFE-GC has been reviewed by Maeda and Hobo (1992). Online coupling of supercritical fluid extraction to gas chromatography has been applied to the analysis of aroma compounds by Hawthorne et al (1988aHawthorne et al ( ,b, 1989a, Lohleit and Bachmann (1990), Huston and Ji (1991), Nielsen et al (1991), and Hartonen et al (1992).…”

Supercritical Fluid Chromatography and Extraction

“…SFE conditions were chosen so that the methyl esters were selectively eluted from the solid catalyst. A cryotrap/thermal desorption unit external to the GC was used to collect the extracted compounds and introduce them to the GC system in the SFE/GC analysis of volatile oils (401). Murphy and Richter used SFE/GC for the analysis of the pesticide aldrin from several food matrices (402).…”

Supercritical fluid extraction employing a variable restrictor coupled to gas chromatography via a sample pre‐concentration trap

“…The sample cold trap was a stainless steel capillary (105 cm x 0.5 mm i.d.). Excellent agreement was achieved when thyme component recoveries were compared with those obtained from hydrodistilled oil of thyme by GC [14]. These results, however, showed that chromatographic valves and valve materials may be critical in obtaining good results.…”