Patent GB-826110-A (GB)
Title: Chromatographic analysis of a multi-component vapour
IPC: G01N30/46
Filed: 1958-03-21
Abstract: A process for the chromatographic analysis of a multi-component vapour which comprises passing a sample of said multi-component vapour together with an inert carrier gas, usually helium, successively through a first separation zone containing material capable of separating the components of said multi-component sample vapour having high retention times; retaining said components having high retention times, and then passing the remainder of said vapour-inert gas mixture through a second separation zone containing material capable of separating components of the multi-component vapour sample having low retention times; retaining said components having low retention times in said second zone; <PICT:0826110/III/1> <PICT:0826110/III/2> removing said successive specific components having high retention times from said first separation zone, by elution with an inert carrier gas stream as binary mixtures of said carrier gas and successive specific components; removing successive specific component having low retention times from said second separating zone, by elution with an inert carrier gas stream, as binary mixtures of said carrier gas and successive specific components; and successively measuring said eluted binary mixtures to determine the concentrations of the specific components of said multi-component vapour sample.  The thermal properties of the binary mixtures may be measured to determine the concentrations of the substances; generally the property of a stream of an inert carrier gas alone being used for comparison purposes.  Helium carrier gas and multi-component sample vapour are concurrently introduced through conduit 18 to column 10 where the components with low-retention times are separated from the components with high-retention times.  The components with low-retention times together with the carrier gas are passed through conduit 26, valve 28 and conduit 30 to strongly-absorbing column 12 where they are stored.  The carrier gas then passes from column 12 through the measuring cell to the vent. During this period, a stream of helium is also passed through the reference cell and conduit 40 to the vent.  At that predetermined time when it is known that, for a specific sample gas, there are no components with low-retention times remaining in column 10 that all of these weakly-retained components are in column 12, the solenoid valve 28 is actuated by an electric timer (not shown) which switches the valve to the position shown in Fig. 2.  The helium carrier gas continues to flow thereby stripping the now adequately resolved components with high-retention times from column 10 through lines 26 and 42 to the measuring cell 34 where measurement is effected. During this time, the solenoid valve is switched to the position shown in Fig. 2, and there is no flow through column 12.  At the end of a predetermined period of time, when all of the components with high-retention time have been eluted from column 10 and passed through the measuring cell, the electric timer returns the solenoid valve 28 to the position shown in Fig. 1.  By this time, helium is again admitted to column 12 and the components with low-retention time stored in the column are stripped (eluted) from the column and passed through the measuring cell where measurement is made for each component.