Instrumentation: The Inlet System

Mass spectrometers consist of several components, an inlet system for introducing the sample, an ionization source for creating ions, a variable magnetic and/or electric field for separating ions based upon on their mass to charge ratio, and an ion detector.

The inlet system can be as simple as a port through which the sample is injected or inserted into a chamber at high vacuum and heated to achieve vaporization. If the sample is a mixture of compounds, a gas chromatographic inlet system will vaporize the sample and separate the mixture into its components. Mass spectra for each of the components are recorded in succession as the components enter the mass spectrometer. Hence, mass spectra of individual components of a complex mixture can be obtained without prior separation. The mass spectrometer available to the undergraduate organic chemistry teaching laboratory has a gas chromatographic inlet system; a schematic diagram of the instrument is shown in Figure 3 and a photo of the instrument is shown in Figure 4.

Figure 3. Schematic diagram of the GC/MS.

Figure 4. The GC/MS available for organic chemistry students at CU Boulder.

Next section: Instrumentation: The ion source

Copyright information: Original content © University of Colorado, Boulder, Chemistry and Biochemistry Department, 2011. The information on these pages is available for academic use without restriction.