| 摘要 |
<p>This invention relates to a modulator for use in gas chromatographic analyses, in particular for comprehensive two-dimensional gas chromatography, adapted to alternatively trap and release fractions of solutes in a length of a capillary column within a chromatographic oven, of the type comprising one nozzle placed to spray one jet in one corresponding capillary column section along said capillary column length, said nozzle being connected to a source of liquid CO2 and means for alternatively causing a jet of gaseous CO2 to impinge during a predetermined time on said capillary column section and to leave the oven atmosphere to heal said capillary column section after said predetermined time. By controlling said capillary column section cooling time by the single jet and said column section heating time by the oven atmosphere in each modulation cycle comprising a heating time and a cooling time a perfect modulation of the sample fractions can be ontained.</p> |
