Figure 4.23
(a) Isothermal separation of homologous series of alkanes at 150°C. Column 3%
Apiezon-L on 100–120 mesh VarAport 30. Carrier gas helium at 10 ml min–^1.^
(b) Sample and column as (a) but temperature-programmed separation showing
the greater range of hydrocarbons, which can be resolved in a shorter time.
(Reproduced by permission of Varian Associates from McNair and Bonelli,
Basic Gas Chromatography, p. 190)between runs to save time is now commonplace. An example of the temperature programmed
separation of a complex mixture is shown in Figure 4.24.
Non-volatile and Thermally Sensitive Compounds
Paints, plastics, polymers, ionic and many biologically important compounds fall into this category.
They can either be pyrolysed under controlled conditions to produce characteristic lower molecular
mass and therefore volatile products or, in some cases, converted into related and more volatile
derivatives.
Pyrolysis GC involves the rapid and controlled thermal decomposition of