Nitrogen chemiluminescent reactions

The chemiluminescence reaction between nitrogen monoxide and ozone is formulated as ... 

Chemiluminescent techniques have been used to determine nanomolar quantities of nitrate and nitrite in seawater [124,125]. This method depends on the selective reduction of these species to nitric oxide, which is then determined by its chemiluminescent reaction with ozone, using a commercial nitrogen oxides analyser. The necessary equipment is compact and sufficiently sturdy to allow shipboard use. A precision of 2nmol/l is claimed, and an analytical range of 2nmol/l with analysis rates of 10-12 samples hourly. 

Chemiluminescent Reactions of Active Nitrogen with Hydrocarbons... 

Gas chromatography is one of the most powerful analytical techniques available for chemical analysis. Commercially available chemiluminescence detectors for GC include the FPD, the SCD, the thermal energy analysis (TEA) detector, and nitrogen-selective detectors. Highly sensitive detectors based on chemiluminescent reactions with F2 and active nitrogen also have been developed. 

The NO + 03 chemiluminescent reaction [Reactions (1-3)] is utilized in two commercially available GC detectors, the TEA detector, manufactured by Thermal Electric Corporation (Saddle Brook, NJ), and two nitrogen-selective detectors, manufactured by Thermal Electric Corporation and Antek Instruments, respectively. The TEA detector provides a highly sensitive and selective means of analyzing samples for A-nitrosamines, many of which are known carcinogens. These compounds can be found in such diverse matrices as foods, cosmetics, tobacco products, and environmental samples of soil and water. The TEA detector can also be used to quantify nitroaromatics. This class of compounds includes many explosives and various reactive intermediates used in the chemical industry [121]. Several nitroaromatics are known carcinogens, and are found as environmental contaminants. They have been repeatedly identified in organic aerosol particles, formed from the reaction of polycyclic aromatic hydrocarbons with atmospheric nitric acid at the particle surface [122-124], The TEA detector is extremely selective, which aids analyses in complex matrices, but also severely limits the number of potential applications for the detector [125-127],... 

In the chemiluminescent detection of nitrogen oxides, a constant source of ozone reacts with a metered air sample containing nitric oxide. Fontijn et al. suggested that this method could also be used for ozone detection by using a constant nitric oxide source for reaction with ozone in the air sample. The ozone-nitric oxide reaction is carried out at reduced pressure, to avoid quenching the chemiluminescent reaction. Detection of the emission in the spectral r on involved (600-3,000 nm) requires using a near-infrared-sensitive photomultiplier tube. The noise of such a photomultiplier tube is reduced by cooling it to about - 20 C. ... 

The chemiluminescence emission resulting from the oxidation of luminol (5-amino-2,3-dihydro-l,4-phthalazinedione) has been extensively studied since its discovery by Albrecht in 1928. Although luminol oxidation is one of the most commonly applied chemiluminescent reactions, to date no definitive mechanism is known . Efficient chemiluminescence emission is only observed when luminol (25) is oxidized under alkaline conditions. Depending on the medium, co-oxidants are required in addition to molecular oxygen for the observation of light emission, but under any condition, 3-aminophthalate (3-AP) and molecular nitrogen are the main reaction products (equation 10). 

Figure 12.12—Chemiluminescence reactions using ozone. Schematic showing the principle of a nitrogen analyser based on the luminescence of nitrogen monoxide.

Various approaches have been described to convert other nitrogen species to NO before detection by the ozone chemiluminescence reaction. The most common converter is hot molybdenum, which converts all of the higher... 

Near-Infrared Chemiluminescence. The technique of chemiluminescence has been most successfully applied in the atmosphere to the measurement of NO and other oxides of nitrogen through various conversion procedures. Glaschick-Schimpf et al. (115) and Holstein et al. (116) reported results of laboratory kinetic studies in which the H02 concentration was determined through the chemiluminescence reaction system shown in equations 28 and 29. It involves the same molecular transitions in the near-infrared as discussed previously (for H02 emission from the 2A state). 

The luminol detector is based on the sensitive chemiluminescent reaction between N02 and luminol in solution. The luminol in alkaline solution reacts with N02 to produce intensive CL centred on 425 nm. The detector cell itself is a 15 cm x 8 cm x 2 cm rectangular block, with inlets and outlets for the carrier gas and luminol flows. The reaction cell contains a fabric wick that is wetted with the luminol solution (1 x 10-4M luminol, 0.2MNa2SO3, 0.05M NaOH, 1.5 x 10 4 ethylenediaminetetraacetic acid and 0.1% surfactant). The wick is viewed by a PMT through an acrylic window, which is transparent to the chemiluminescent light at 425 nm. When a N02 peak enters the cell, a fraction of the N02 dissolves in the solution on the surface of the wick, which then reacts with luminol to ultimately yield a strong CL. The results described indicate that this detector may be successfully used for the sensitive and selective detection of any nitrogen-containing species that may thermally decompose to yield N02, with a potential use for the detection of explosives (2,4-DNT and TNT). 

Nitrogen chemiluminescence takes place in a reaction cell, under vacuum, where the emitted light is measured using a photomultiplier tube. The primary combustion products from a methanol-modified SFC mo-... 

A more spectacular gaseous titration technique is used for the estimation of the concentrations of various atomic species. This involves the use of a fast flow discharge apparatus and the spectroscopic estimation of the extent of various chemiluminescent reactions. Hydrogen and nitrogen atoms may both be titrated with NO, and oxygen atoms with N02 or the reactions being... 

Chemiluminescent Reactions of Excited Helium with Nitrogen and Oxygen... 

Bawn and Evans [110] report chemiluminescent reactions of nitrous oxide and nitrogen dioxide with gaseous sodium. The luminescence (sodium D line) decreases with rise of temperature and the chemiluminescence flame is smaller than the normal flame. The mechanism proposed... 

Obenauf et al. [271] have measured the quantum yield of fluorescence per molecule of target gas consumed in the reaction of barium vapour with nitrogen dioxide and nitrous oxide, obtaining values of 0.20—0.27 for the stronger fluorescence from the nitrous oxide reaction, and 0.015 0.003 for the nitrogen dioxide reaction. Using the values for total reaction cross-section reported by Jonah et al. [270], Obenauf et al. [271] estimate the cross-sections for the chemiluminescent reactions to be < 6—7 for the nitrous oxide reaction and about 2—3 for the nitrogen dioxide reaction. 

Considerable interest is being shown in the chemiluminescent reactions of barium. Much of this work is directed towards measurements of photon yields and determination of rotational—vibrational excitation in the various states. The reaction between barium and nitrous oxide has evoked most interest [374—378]. In the chemiluminescent reactions between barium and nitrosyl chloride [377, 379], nitrogen dioxide [374], nitric oxide[374], oxygen [374] and ozone [374], electronically excited BaO is produced, except with nitrosyl chloride which produces BaCl. 

Among other methods is that based on the chemiluminescent reaction of nitrogen oxide with ozone ... 

---