Identification microcoulometric detector

Positive identification of low-ppb (pg/L) levels of endosulfan in human blood has been achieved by GC equipped with a microcoulometric detector (GC/MC) (Griffith and Blanke 1974). Although GC/MC is specific and nearly as sensitive as GC/ECD for detecting endosulfan in blood, GC/MC is more difficult to operate. Both isomers of endosulfan can be measured in blood using a method described by Guardino et al. (1996). According to the authors, endosulfan can be recovered and measured with an approximate limit of quantitation (LOQ) of 0.2 pg/L (sub-ppb). 

Various procedures described by Crippen and Smith (5) are available for identifying components in a chromatogram. Because of the limitations mentioned above, the choice of method was restricted. Peak identifications for this sample relied on cleanup and preliminary separation by column adsorption chromatography with activated alumina and Florisil, use of the chlorine- and sulfur-specific microcoulometric detector, and parallel injections onto three or more columns containing liquid substrates varying widely in polarity. 

The halogen selective microcoulometric and electrolytic conductivity detectors have been applied extensively to the analysis of halogenated compounds in drinking water. Both have adequate sensitivity for the application and sufficient selectivity to allow reasonably accurate identifications with the retention time data. However, these detectors are also best applied to well defined samples where the probability of unexpected compounds is low. 

Gas Chromatographic Measurement and Identification of Pesticide Residues with Electron Capture, Microcoulometric, and Electrical Conductivity Detectors... 

As the title of this paper indicates, it is concerned only with the use of the electron capture, microcoulometric, and electrolytic conductivity detectors for quantitation and identification of pesticide residues. Further background information on gas chromatographic detectors may be found in the paper by Westlake and Gunther (I). 

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