GCxMS of diesel: a two-dimensional separation approach.

Comprehensive two-dimensional gas chromatography can be viewed as a traditional gas chromatography with a sophisticated "elution-resolved" flame ionization detector (GC/FID) or a detector with separation capability. The concept of multidimensional chromatography can be extended to other detectors that also have separation capability, such as ultraviolet, infrared, and mass spectrometer. Mass spectrometry, combined with gas chromatography, GC/MS, has been a powerful separation/identification device for many years. However, if one applies the multidimensional separation concept to this combination with a nonfragmentation ionization method, GC/MS not only can be used as a separation/identification tool, but also a two (multiple) dimensional separation device, GCxMS. In this study, a two-dimensional separation (GCxMS) study of diesel composition is demonstrated and compared with the GCxGC technique. The major advantage of GCxMS is the compound class separation. The compound groups within a compound class are also well-separated on the basis of their parent masses. Because of the exact mass operation, the specific element containing compound distribution can also be generated through the extraction of specific mass groups. For qualitative analysis, GCxMS is a technique where one experiment can generate a wide range of information. GCxMS may also perform quantitative analysis when appropriate response factors for various compound groups are available. From GCxGC to GCxMS, the power of two (multiple) dimensional separation has just started exposing its advantages for complex mixture analysis. To achieve multiple dimensional separation in different forms, many improvements remain to be made. The challenge now is to combine/accommodate two or more different techniques to solve a specific complex separation problem. The GCxMS experience has pushed this effort one step ahead toward complete application of this new concept in the analysis of complex mixtures.