Chapter One

The combination of gas liquid chromatography (GC) for separation and mass spectrometry (MS) for detection and identification of the components of a mixture of compounds is rapidly becoming the definitive analytical tool in the research and commercial analytical laboratory. The GC/MS systems come in many varieties and sizes depending on the work they are designed to accomplish. Since the most common analyzer used in modern mass spectrometers is the quadrupole, we will focus on this means of separating ion fragments of different masses. Discussion of ion trap, time-of-flight, Fourier transform mass spectrometry (FTMS), and magnetic sector instruments will be reserved for latter sections in the book.

The quadrupole operational model is the same for bench top production units and for floor standing research instruments. The actual analyzer has changed little in the last 10-12 years except to grow smaller in size. High vacuum pumping has paralleled the changes in the analyzer, especially in the high efficiency turbo that have shrunk to the size of a large fist in some systems. Sampling and injection techniques have improved gradually over the last few years.

The most dramatic changes have been in the area of control and processing software and data storage capability. In the last 10 year, accelerating computer technology has reduced the computer hardware and software system shipped with the original system to historical oddities. In the face of newer, more powerful, easier to use computer systems, the older DEC 10, RTE (a Hewlett-Packard minicomputer GC/MS control system) and Pascal-based control and da