| 摘要 |
1309678 Quantitative gas chromatography BALZERS PATENT-UND BETEILIGUNGS AG 26 May 1970 [18 June 1969] 25123/70 Heading B1X In the quantitative determination of elements and/or isotopes contained in individual compounds of a mixture of substances the mixture is first separated into the individual compounds by a first gas-chromatography column. The compounds are then subjected to a chemical reaction e.g. combustion with a catalyst e.g. Pt, Pd, CuO, PbO 2 CO 3 O 4 or a hot copper capillary oxidised inside, and the reaction products then passed directly by the carrier gas, e.g. N 2 , without mixing to a second gas chromatography column acting as a storage column to build up the concentrations of the reaction products. When the initial mixture has been completely separated the temperature of the storage column is raised e.g. by electric resistance, direct heating or by a movable heater, and the reaction products eluted with a slower flow of optionally different carrier gas and then passed to a selectively responsive detector e.g. a mass spectrometer or a thermionic detector. The first column may be packed with a liquid methyl polysiloxane on kieselguhr or a silicone rubber preparation on Kieselguhr made hydrophobic by treatment with di-methyl-dichloro-silane. The accumulator column may be packed with kieselguhr, aluminium oxide or sodium-aluminium silicate. The mixtures to be analysed may contain <SP>14</SP>C marked methyl esters of the C 10-18 fatty acids, tri-methylsilised products from photosynthesis marked by <SP>14</SP>C from a chloroplast preparation, or n-hexane/ acetone extracts from vegetable material to be investigated for insecticides. |
