Chapter 1 - What Is GC/MS?

Abstract

This chapter provides a brief introduction to gas chromatography/mass spectrometry (GC/MS). The operating principle of a gas chromatograph includes volatilization of the sample in a heated inlet port, separation of the components of the mixture in a prepared column, and detection of each component by a detector. Carrier gases such as hydrogen or helium are important elements of the gas chromatograph. It is used to transfer the sample from the injector through the column, and into the detector. The interface in GC/MS is a device for transporting the effluent from the gas chromatograph to the mass spectrometer. The most common mass spectrometers interfaced to gas chromatographs are called “quadrupole” and “magnetic-sector instruments.” The detection of ions in GC/MS is performed exclusively using an electron multiplier. There are two types of electron multipliers: the continuous dynode type and the discrete type. The chapter discusses various ionization methods such as electron impact ionization, chemical ionization, and negative ion chemical ionization.