Capillary Chromatography - The Resolution of Some Polynuclear Aromatic Hydrocarbons 1

The Resolution of Some Polynuclear Aromatic Hydrocarbons

 

An example of the separation of a polynuclear aromatic hydrocarbon mixture is shown in figure 35. The column was 25 m long, 0.22 mm I.D. and carried a film of stationary phase 0.1 mm thick. The initial temperature was 80ûC which was raised to 290ûC at a rate of 5ûC/min. and held at 290ûC for 10 min. A split injector was used to place the sample on the column. Hydrogen was used as the carrier gas at an inlet pressure of 10 psi. The detector employed was, again, an FID. It is seen that the polynuclear aromatics are well resolved and there is only slight column bleed at 290ûC. It is also clear, however that this stationary phase, beitmay a carborane, can not be used much above 290ûC before column bleed would be unacceptable.

 

The film thickness of the carborane stationary phases is usually kept fairly small (e.g. 0.1 mm) and, although primarily designed for high temperature operation, can also be used very effectively at normal operating temperatures. An example of the use of the same high temperature stationary phase to separate some substituted benzenes at relatively low temperatures is shown in figure 36.

 

 

Courtesy of SGE Ltd.

 

1. Naphthalene 6. Anthracene 11.Benzo(b)anthracene
2. Acenaphthalene 7. Fluoranthen 12.Benzo(a)pyrene
3.Acenaphthene 8. Pyrene 13.Indent(1,2,3cd)pyrene
4. Fluorene 9. Benzo(a)anthracene 14Dibenzo(a,h)anthracene
5. Phenanthrene 10.Chrysene 15.Benzo(g,h,i)perylene

 

Figure 35. The Separation of Some Polynuclar Aromatic Hydrocarbons

 

The column was 25 m long, 0.32 mm I.D. and carried a film of stationary phase 0.1 mm thick. Initially, the column was held at 40 ûC for 2 min. and the temperature was then raised to 70ûC at a rate of 5ûC/min. and finally held at 70ûC for 4 min. A split injector was used to place the sample on the column. Hydrogen was used as the carrier gas at an inlet pressure of 6 psi. and the detector employed was an FID.