Detectors hybrid/multiple detector

Besides the universal detector systems, for example electron capture, flame ionisation and thermal conductivity usually coupled with gas chromatographic columns, various other detectors are now being used to provide specific information. For example, the gas chromatograph/mass spectrometer couple has been used for structure elucidation of the separated fractions. The mechanics of this hybrid technique have been described by Message (1984). Other techniques used to detect the metal and/or metalloid constituents include inductively coupled plasma spectrometry and atomic absorption spectrometry. Ebdon et al. (1986) have reviewed this mode of application. The type and mode of combination of the detectors depend on the ingenuity of the investigator. Krull and Driscoll (1984) have reviewed the use of multiple detectors in gas chromatography. 

There are three types of WDXRF instruments sequential spectrometers, which use a goniometer and sequentially measure the elements by scanning the wavelength simultaneous spectrometers, which use multiple channels, with each channel having its own crystal/detector combination optimized for a specific element or background measurement and hybrid spectrometers, which combine sequential goniometers or scanners with fixed channels as well as XRD channels and goniometers. Hybrid instruments will be discussed in Section 8.4 with XRD instruments. 

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