Basic Principles of Gas Chromatography

Interfaces for Coupling Gas Chromatography with Mass Spectrometry 

Electron ionization (El) and chemical ionization (Cl) ion sources are both compatible with the gas-phase GC-eluting components. El especially provides both molecular ion and fragment ion information that can be used independently 

Of these, partition chromatography, especially the reversed-phase (RP) mode, is the most widely used technique for the separation of several classes of compounds. In RP-HPLC (see Table 5.1), the stationary phase is a nonpolar matrix and the mobile phase is a polar solvent (e.g., water mixed with a polar organic modifier such as methanol, isopropanol, or acetonitrile). Mobile phase and stationary phase both play prominent roles in the separation mechanism. A sample is applied onto the head of a column filled with an appropriate stationary phase. The 

Column Dimensions (Length x i.d., in mm) Flow Rate (qL min ) Injection Volume (qL) 

Partition chromatography is also practiced in the normal-phase mode, in which the stationary phase is a polar matrix and the mobile phase at the start of the separation is a polar solvent. The polar solutes prefer to remain in the stationary phase and elute late. 

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