ABSTRACT
This chapter discusses the conceptual basics for understanding the rationale behind the vital steps of gas chromatography (GC)-mass spectrometry (MS) operations before taking on any GC-MS related tasks such as method development or routine procedures. The purpose of the ionization process is to supply energy to an analyte molecule so that the molecular structure will break apart in a characteristic manner. Two different ionization techniques, such as electron ionization (EI) and chemical ionization (CI), are sometimes necessarily used together in a GC-MS procedure to successfully identify the analyte so that mass spectral information derived from each ionization technique complement each other: EI to obtain structural information; CI to give molecular mass information. The key role of the mass analyzer in a GC-MS system is to separate ions according to their mass-to-charge ratios. Mass range, data acquisition rate, and resolving power are the key attributes that characterize a mass analyzer.
