Redox chemiluminescence

More recently, chemiluminescence detectors based on redox reactions have made possible the detection of many classes of compounds not detected by flame ionization. In the redox chemiluminescence detector (RCD), the effluent from the column is mixed with nitrogen dioxide and passed across a catalyst containing elemental gold at 200-400°C. Responsive compounds reduce the nitrogen dioxide to nitric oxide. The nitric oxide is reacted with ozone to give the chemiluminescent emission. The RCD yields a response from compounds capable of undergoing dehydrogenation or oxidation and produces sensitive emissions from alcohols, aldehydes, ketones, acids, amines, olifins, aromatic compounds, sulfides, and thiols. 

S. Nyarady, R. Barkley, et al., Redox chemiluminescence detector application to gas chromatography, Anal. Chem., 37 2074-2079... 

S. Montzka and R. Sievers, Redox chemiluminescence detectors for chromatography, Chromatography, 2 22-26 (1987). 

Reviews have appeared of the photophysics of molybdenum complexes, primary and secondary processes in organometallic chemistry, flash photolysis of Pe(CO)5 and Cr(CO)g, dinuclear manganese carbonyl compounds, the photochemistry of metal complexes isolated in low temperature matrices, cluster complexes, diene complexes, photoproduction of coordinativeiy unsaturated species containing rhodium or iridium, and redox chemiluminescence of organometallic compounds.Synthetic and metal organic photochemistry in industry has also been reviewed. 

Oxygen-18 studies of the chemiluminescence of a firefly luciferin analogue have provided evidence which contradicts other earlier reports in that it suggests that the dioxetanone is an important intermediate in light production.304 Spin-statistical contributions in redox chemiluminescence quantum efficiency have been analysed,305 and a striking deuterium isotope effect in phosphorus chemiluminescence has been discovered.800... 

The redox chemiluminescence detector (RCD) is also based on the nitric oxide-ozone reaction. However, unlike the two detectors previously described, the analytes do not contain any oxidizable nitrogen. In this case a nitrogen-containing reagent such as nitrogen dioxide or nitric acid is reduced to nitric oxide by the analyte at a heated gold surface (reaction [IV]) ... 

TEA, thermal energy analyzer NSD, nitrogen selective detector RCD, redox chemiluminescence detector. 

This group of reactions includes redox, chemiluminescence, dissociation, and complex-formation reactions. 

This reaction mechanism was first proposed by Halsted and Thrush (30) when studying the kinetics of elementary reactions involving the oxides of sulfur. Visible and UV spectroscopic studies (31) confirmed that the chemiluminescent emission was from SO2. Recently, it has also been confirmed that the sulfur- analyte molecule from the GC effluent is converted to SO in the flame of the SCD (32). Even though SO is a free radical, it can be sufficiently stabilized in a flow system under reduced pressure (33,34) to be sampled and transferred to a vessel to react with introduced O. Based on these operational principles. Burner and Stedman (33) concluded that SO produced in a flame could be easily detected. They modified a redox chemiluminescence detector (36) to produce what was termed a Universal Sulfur Detector (USD). A linear response between 0.4 ppb and l.S ppm (roughly equal to 3 to 13,000 pg of S/sec) was demonstrated with equal response to the five sulfur compounds tested. This detection scheme has been utilized as the basis for the commercially available GC detector. 

PTV programmed-temperalure vaporization r column radius RCD redox chemiluminescence detector peak resolution... 

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