| 摘要 |
<PICT:0925933/III/1> A device for gas chromatography using a capillary column comprises a pair of connections for said column, one of which is connected to a carrier gas line provided with a vent line having a throttle valve therein and the other of which is connected to a measuring element. Preferably the vent line is removable and can be replaced by a connecting line for a packed column in place of the capillary column. As illustrated, carrier gas enters through line 1 and passes to capillary column connection 2. The valved vent line is shown at 3 and the packed column at 13. After passage through the capillary column the gas stream enters connection 5 and is passed into a stream of hydrogen or other combustible gas entering through line 7 and reduced in velocity by resistance coil 11. The mixed gases are burned in an ionisation chamber having ignition coil 12 and grid 10 and thereafter removed through outlet 16. The chamber is kept above atmospheric pressure by means of compressed air line 17. The ionisation current flowing between grid 10 and burner 8 (between which a potential of 200 v. is maintained) is a function of the gas in the chamber. A tube 14 to the lower part of which the outlet of the alternative packed column can be attached, is provided with a branch 18 for connection to a second form of detector such as a heat conductivity cell, and a resistance coil 17 which determines the ratio of the flows through lines 14 and 18. By using both detectors, it is possible to measure simultaneously trace gases and chief components or organic components (e.g., CH4 and C2H5, with the ionisation detector) and inorganic components (e.g., N2 and O2). Specification 834,390 is referred to. |
