Interfacing Mass Spectrometers with Gas Chromatographs

There are several methods available for interfacing gas chromatographs with mass spectrometers. These include the use of jet separators for packed columns and a variety of ways of interfacing capillary columns. For packed columns the jet separator, a form of momentum separator, is required to remove the majority of the carrier gas. A 'solvent dump valve' is also incorporated into these devices in order that the injection solvent can be vented to waste rather than it passing into the mass spectrometer.

Although a number of interfaces for packed column GC-MS have been described in the past, capillary columns are currently almost exclusively used for GC-MS. The most widely used interface, in this case, is the direct interface, where the column is passed through a simple heated transfer line directly into an EI or CI ion source. The low (1 mL min"1) carrier gas flow commonly used with capillary columns can readily be accommodated by the MS pumping system in order to maintain a good vacuum. Figure 3 shows a complete instrument based around the use of a capillary column, a simple direct interface and a quadru-pole mass spectrometer. For a more complete discussion of the full range of GC-MS interfaces see either Chapman (1993) or Johnstone and Rose (1996).

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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