Thermal ionization mass spectrometry detection systems

A number of other laser spectroscopic techniques are of interest but space does not permit their discussion. A few specialized methods of detecting laser absorption worthy of mention include multiphoton ionization/mass spectrometry (28), which is extremely sensitive as well as mass selective for gas-phase systems optically detected magnetic resonance (29) laser intracavity absorption, which can be extremely sensitive and is applicable to gases or solutions (30) thermal blooming, which is also applicable to very weak absorbances in gases or liquids (31) and... 

As seen in Chapter 9.C.2, a very wide variety of organics are found in particles in ambient air and in laboratory model systems. The most common means of identification and measurement of these species is mass spectrometiy (MS), combined with either thermal separation or solvent extraction and gas chromatographic separation combined with mass spectrometry and/or flame ionization detection. For larger, low-volatility organics, high-performance liquid chromatography (HPLC) is used, combined with various detectors such as absorption, fluorescence, and mass spectrometry. For applications of HPLC to the separation, detection, and measurement of polycyclic aromatic hydrocarbons, see Wingen et al. (1998) and references therein. 

There are three types of detectors Thermal Conductivity Detector (TCD), Flame Ionization Detector (FID) and Electron Capture Detector (ECD). In these detector systems, EID exhibits the highest sensitivity for the detection of hydrocarbon materials and TCD has been used commonly for the detection of inorganic components and organic materials except for hydrocarbons. The ECD is used specifically for the detection of materials with large electronegativity, such as alkyl halides. Recently, GC has been equipped with a mass spectrometry system (GC-MS). 

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