Flame ionization detector response characteristics

Several methods have been developed which seek to escape the inherent nonlinearity of the nondispersive infrared analyzer by the use of other detectors. The flame ionization detector commonly used in gas chromatography has many useful characteristics, including sensitivity and linearity of response, but it does not respond equally to all carbon compounds it does not respond at all to carbon dioxide. Therefore, the organic compounds must be converted to a single organic compound... 

The NMR spectra were recorded on Bruker AC200 (200 MHz) and AC300 (300 MHz) spectrometers at ambient temperature in NMR solvents obtained from ISOTEC Inc.. G.C. analysis were performed on Unicam PU4600 and PU610 apparatus with 30 m J W Scientific DB-1, DB-17 and AT-SILAR capillary columns and flame ionization detectors. Product yields were determined by peak area analysis response factors for selected substrates and products were foimd to be virtually identical. Internal standards were used in the initial stage of this study, but were found to influence the catalyst characteristics. G.C.M.S. was performed on a Unicam Automass apparatus combined with 610 series G.C. apparatus equipped with 30 m J W Scientific DB-1 and DB-17 columns. TEM-EDAX was performed on a Phillips CM 200 microscope equipped with a field emission gun. TEM-EDAX samples were prepared by application of a few droplets of a suspension of the catalyst in ethanol onto a holey carbon film which was supported by a nickel grid after which the ethanol was allowed to evaporate. 

When a flame ionization detector is used, regularly remove the deposits formed in the detector from combustion of the silicone liquid phase decomposition products. These deposits will change the response characteristics of the detector. 

The identification of the chemical forms of an element has become an important and challenging research area in environmental and biomedical studies. Two complementary techniques are necessary for trace element speciation. One provides an efficient and reliable separation procedure, and the other provides adequate detection and quantitation [4]. In its various analytical manifestations, chromatography is a powerful tool for the separation of a vast variety of chemical species. Some popular chromatographic detectors, such flame ionization (FID) and thermal conductivity (TCD) detectors are bulk-property detectors, responding to changes produced by eluates in a characteristic mobile-phase physical property [5]. These detectors are effectively universal, but they provide little specific information about the nature of the separated chemical species. Atomic spectroscopy offers the possibility of selectively detecting a wide rang of metals and nonmetals. The use of detectors responsive only to selected elements in a multicomponent mixture drastically reduces the constraints placed on the separation step, as only those components in the mixture which contain the element of interest will be detected... 

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