Investigations of a new field in gas chromatography: Capillary columns with a super-thick layer of stationary liquid phase

Abstract

Basic characteristics (efficiency, selectivity, non-equilibrium) of capillary columns with a super-thick layer of stationary liquid phase are investigated. In contrast to traditionally used capillary columns with standard stationary phase thickness of 0.1–0.5 um, some new variables are now established. Firstly, the values of relative retention depend on carrier gas linear velocity. Secondly, the asymmetry of chromatographic peaks increased in accordance with the increase in carrier gas velocity. Thirdly, it was theoretically and experimentally shown that dependence of the height equivalent to a theoretical plate (HETP) on carrier gas velocity is linear. The above noted variables are evidences that the new type of GC is realized under these conditions. The use of capillary columns with super-thick layer of stationary liquid phase is practical when the following problems have to be solved: (1) Separation of highly volatile substances; (2) Preliminary concentration of trace compounds from strong diluted samples; (3) Improvements in measurement and accuracy due to the advantages of splitless injection into wide bore columns with super-thick films. Solutions to some analytical tasks while using super-thick stationary liquid phase are shown: (1) Large volume injection into capillary column with sample transfer speed up to 100 μL min −1; (2) Isothermal splitless injection; (3) Separation of low boiling compounds; (4) Separation of polar substances (alcohols).