Chemiluminescent phenomena

The Montroll-Shuler equation can also predict how fast a molecule which is created in a highly excited vibrational state will decay to the equilibrium state. This is of interest in connection with chemiluminescence phenomena. In certain cases one finds experimentally that this relaxation is much faster than what one would expect from the master equation of Montroll and Shuler and improved versions of this equation. One possible mechanism for this fast relaxation is that although most of the collisions in which the diatomic molecule participates are between the diatomic molecule and an inert gas atom, there will also be some collisions between diatomic molecules. In the latter case we have the situation where two diatomic molecules in quantum state n collide producing, with fairly high probability, molecules in quantum states n I and n + 1, respectively. The number of such collisions is, of course quite small compared to the number of collisions of the first kind, but since they are so extremely efficient they may still be of importance. This mechanism, we believe, was first suggested in connection with chemiluminescence by Norrish in a Faraday Society discussion.5 The equations describing this relaxation had, however, been discussed several years earlier by Shuler6 and Osipov.7... 

The organic chemist s interest in chemiluminescent phenomena was aroused first by Albrecht s (1928) report of light emission from the reactions of luminol (5-amino-2,3-dihydrophthalazine-l,4-dione) [32], Since that time there have been innumerable investigations of this system and its close relatives. There have also been excellent reviews of much of this work, the most recent being by Roswell and White (1978). Herein we will present a broad summary of this work and some comments on recent work on analogous compounds. 

In addition to the use of spatially-resolved concentration measurements for the determination of rate constants for reactions of ground state atoms, the discharge-flow method has been extensively applied to kinetic and spectroscopic studies of chemiluminescent phenomena. In these cases, the flow parameters in the flow tube are of no great importance, as time resolution is not obtained from axial displacements consequently, the total pressures and flow rates, and tube diameters may be varied over wide limits, since it is unnecessary to ensure adherence to the conditions for plug flow. 

However, since hydrocarbon flames are especially effective in producing chemiluminescence phenomena, the following reactions also may provide excitation energy for the metal atoms ... 

Horseradish peroxidase- (Ushijima etal. 1985) or myeloperoxidase-catalysed tyrosine oxidation (Ushijima et al. 1997) accompanies light emission in the visible region. Similar chemiluminescence phenomena have been obtained during the fertilisation of sea urchin eggs, which forms bityrosine crosslinks in the egg membrane (Takahashi et al. 1989), during incubation of tyrosine-rich bamboo shoot extract with HjOj (Totsune et al. 1993), and during activation of human phagocytic leucocytes by opsonized zymosan in the presence of absence of added tyrosine (Ushijima et al. 1997). Tyrosine... 

Most of the sensors using a consumable reagent are based on a chemiluminescence phenomenon that is revealed by a reagent such as trichlorophenyl oxalate (TCPO) and a fluorophore (usually a fluoranthene), or luminol. 

Luminol (3-aminophthalhydrazide) is used in a commercially available portable device called the Luminox that measures minute concentrations (parts per billion) of the pollutant nitrogen dioxide in air. Luminol is also used ftequently in laboratory demonstrations of the chemiluminescence phenomenon. Luminol-mediated chemiluminescence is the result of an oxidation reaction. The oxidation proceeds in two steps, which ultimately lead to the production of the aminophthalate anion in an excited state and the elimination of water and molecular nitrogen. The formation of the strong triple bond (N=N) is a major factor in the release of energy in the form of light. 

The emission yield from the horseradish peroxidase (HRP)-catalyzed luminol oxidations can be kicreased as much as a thousandfold upon addition of substituted phenols, eg, -iodophenol, -phenylphenol, or 6-hydroxybenzothiazole (119). Enhanced chemiluminescence, as this phenomenon is termed, has been the basis for several very sensitive immunometric assays that surpass the sensitivity of radioassay (120) techniques and has also been developed for detection of nucleic acid probes ia dot-slot. Southern, and Northern blot formats (121). 

Data for temperature coefficients (activation energies) given in Table 2 show one common phenomenon when plotting chemiluminescence intensity vs. temperature in Arrhenius coordinates, namely, that in the higher temperature range the activation energy is usually higher than at lower temperatures, which is... 

The maximum of luminol chemiluminescence emission is at 425 nm in aqueous and at 480 nm in DMSO-containing solvent. It was suggested that different anions of 3-aminophthalate were responsible for this phenomenon, namely 51 (in water) and 52 (in aprotic solvents). 

Intermolecvlax energy transfer is apparently involved in the anomalous chemiluminescence of phthalic hydrazide in aprotic solvent (DMSO/tert.BuOK/Og) 124) the energy of excited phthalated ianion is transferred to phthal-hydrazide monoanion which then emits at 525 nm with relatively low quantum yield. This phenomenon has not been observed in aqueous systems 2>. 

Fluorescence may be decreased or completely eliminated by interactions with other chemical species. This phenomenon is called quenching of fluorescence. Obviously, if the fluorescence of a fluorophore generated in a CL reaction is quenched the observation of chemiluminescence will be precluded. 

Chemiluminescence (CL) is the emission of the electromagnetic (ultraviolet, visible, or near infrared) radiation by molecules or atoms resulting from a transition from an electronically excited state to a lower state (usually the ground state) in which the excited state is produced in a chemical reaction. The CL phenomenon is relatively uncommon because, in most chemical reactions, excited molecules... 

For more than 30 years, the phenomenon of luminescence—originally a curiosity in the physical laboratory—has been the basis of a well-established and widely applied spectrometric branch of analytical chemistry. Specifically, chemiluminescence (CL)-based analysis is growing rapidly, offering a simple, low-cost, and sensitive means of measuring a variety of compounds. Owing to elegant new instrumentation and, especially, to new techniques, some of which are entirely new and some borrowed from other disciplines, CL and bioluminescence (BL) can now be routinely applied to solve diverse qualitative and quantitative analytical problems. 

All integrated sensors based on an interaction between the analyte and reagent (neither of which is used in a retained form) and regeneration of the latter rely on chemiluminescent reactions involving electroregeneration of the reagent or a quenching phenomenon. On the other hand, absorptiometric and reflectometric sensors of this type use colorimetric acid-base indicators supported on a suitable material. 

Chemiluminescence. That PMNs stimulated to undergo the respiratory burst cause the emission of light has already been mentioned. Whatever the species which actually emit photons, the phenomenon appears to be dependent on 02 and H2O2 seems faithfully to reflect the activity of the burst is enhanced by scavengers... 

An interesting phenomenon which may be related to this precursor state is the chemiluminescence which has been reported in the disproportionation of alkoxy radicals.16 In the case of CH30 radicals the reaction is ... 

Abstract Cataluminescence (CTL) is chemiluminescence emitted in a course of catalytic oxidation. Since 1990, the present authors and coworkers have observed CTL during the catalytic oxidation of various organic vapors in air. This phenomenon has been applied to the CTL-based sensors for detecting combustible vapors. THE CTL response is fast, reproductible and proportional to the concentration of the combustible vapors of ppm orders in air. Based on two types of models of the CTL, the relationship between the CTL intensity and the rate of catalytic oxidation have been investigated analytically. In this article, the effects of catalyst temperature, gas flow-rate and gas concentration on the CTL intensity are demonstrated. Finally, various types of sensing system using the CTL-based sensor are proposed. The results of discrimination and determination of more than ten types of vapors of various concentrations are shown. 

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