3: Analysis of Pesticide Residues by Chromatographic Techniques Coupled with Mass SpectrometryWang Jing, Jin Maojun, Jae-Han Shim, and A.M. Abd El-Aty; 3.1 Overview of Chromatography-Mass Spectrometry; 3.2 The Basic Theory of Mass Spectrometry; 3.2.1 The Working Principle of Mass Spectrometry; 3.2.2 Main Performance Parameters Used to Characterize a Mass Spectrometer; 3.2.2.1 Mass Measurement Range; 3.2.2.2 Resolution; 3.2.2.3 Sensitivity; 3.2.3 The Basic Structure of the Mass Spectrometer; 3.2.3.1 Vacuum System; 3.2.3.2 Ion Source; 3.2.3.3 Mass Analyzer; 3.2.3.4 Detector