Phosphorus chemiluminescence

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... 

White Phosphorus Oxidation. Emission of green light from the oxidation of elemental white phosphoms in moist air is one of the oldest recorded examples of chemiluminescence. Although the chemiluminescence is normally observed from sotid phosphoms, the reaction actually occurs primarily just above the surface with gas-phase phosphoms vapor. The reaction mechanism is not known, but careful spectral analyses of the reaction with water and deuterium oxide vapors indicate that the primary emitting species in the visible spectmm are excited states of (PO)2 and HPO or DPO. Ultraviolet emission from excited PO is also detected (196). 

The commonest form of phosphorus, and the one which is usually formed by condensation from the gaseous or liquid states, is the waxy, cubic, white form o -P4 (d 1.8232 gcm at 20°C). This, paradoxically, is also the most volatile and reactive solid form and thermodynamically the least stable. It is the slow phosphorescent oxidation of the vapour above these crystals that gives white phosphorus its most characteristic property. Indeed, the emission of yellow-green light from the oxidation of P4 is one of the earliest recorded examples of chemiluminescence, though the details of the reaction... 

The simultaneous analysis of orthophosphate, glycerol phosphates, and inositol phosphates has been achieved by spectrophotometric analysis of the molybdovanadate complexes. Also, a sensitive and selective chemiluminescent molecular emission method for the estimation of phosphorus and sulphur is described, which is based on passing solutions into a cool, reducing, nitrogen-hydrogen diffusion flame. For organic compounds it was usually necessary to prepare test solutions by an oxygen-flask combustion technique. 

Typically, intense chemiluminescence in the UV/Vis spectral region requires highly exothermic reactions such as atomic or radical recombinations (e.g., S + S + M - S2 + M) or reactions of reduced species such as hydrogen atoms, olefins, and certain sulfur and phosphorus compounds with strong oxidants such as ozone, fluorine, and chlorine dioxide. Here we review the chemistry and applications of some of the most intense chemiluminescent reactions having either demonstrated or anticipated analytical utility. 

The most commonly used and widely marketed GC detector based on chemiluminescence is the FPD [82], This detector differs from other gas-phase chemiluminescence techniques described below in that it detects chemiluminescence occurring in a flame, rather than cold chemiluminescence. The high temperatures of the flame promote chemical reactions that form key reaction intermediates and may provide additional thermal excitation of the emitting species. Flame emissions may be used to selectively detect compounds containing sulfur, nitrogen, phosphorus, boron, antimony, and arsenic, and even halogens under special reaction conditions [83, 84], but commercial detectors normally are configured only for sulfur and phosphorus detection [85-87], In the FPD, the GC column extends... 

White phosphorus ignites in air spontaneously. When placed on a paper, the paper catches fire after a short delay. It catches fire at about 35°C. At room temperature white phosphorus glows in the dark on exposure to air emitting faint green light. Such chemiluminescence is attributed to the oxidation of P4 molecules in the vapor phase in contact with the surface of solid phosphorus ... 

The allotropes of phosphorus may be identified from their physical properties. White phosphorus can be identified from its chemiluminescence (a pale... 

The present volume comprises 17 chapters, written by 27 authors from 11 countries, and deals with theoretical aspects and structural chemistry of peroxy compounds, with their thermochemistry, O NMR spectra and analysis, extensively with synthesis of cyclic peroxides and with the uses of peroxides in synthesis, and with peroxides in biological systems. Heterocyclic peroxides, containing silicon, germanium, sulfur and phosphorus, as well as transition metal peroxides are treated in several chapters. Special chapters deal with allylic peroxides, advances in the chemistry of dioxiranes and dioxetanes, and chemiluminescence of peroxide and with polar effects of their decomposition. A chapter on anti-malarial and anti-tumor peroxides, a hot topic in recent research of peroxides, closes the book. 

Chromatographic methods have included development of element-specific atomic emission, flame photometric, and flame chemiluminescent detectors. For example, a flame chemiluminescent phosphorus detector has been suggested for... 

The most general purpose detector for open tubular chromatography is a mass spectrometer. Flame ionization is probably the most popular detector, but it mainly responds to hydrocarbons and Table 24-5 shows that it is not as sensitive as electron capture, nitrogen-phosphorus, or chemiluminescence detectors. The flame ionization detector requires the sample to contain SlO ppm of each analyte for split injection. The thermal conductivity detector responds to all classes of compounds, but it is not sensitive enough for high-resolution, narrow-bore, open tubular columns. 

J. K. Robinson, M. J. Bollinger, and J. W. Birks, Luminol/H202 Chemiluminescence Detector for the Analysis of NO in Exhaled Breath, Anal. Chem. 1999, 71, 5131. Many substances can be analyzed by coupling their chemistry to luminol oxidation. See, for example, O. V. Zui and J. W. Birks, Trace Analysis of Phosphorus in Water by Sorption Preconcentration and Luminol Chemiluminescence, Anal. Chem. 2000, 72, 1699. 

In a hydrogen-rich flame, combustion of samples containing phosphorus and/or sulfur results in the formation of chemiluminescent species which emit light characteristic of the heteroatom introduced into the flame. Selection of an interference filter with a 394- or 526-nm bandpass allows selectivities for sulfur and phosphorus respectively. Recent work by Krost and co-workers (27) found that a 690-nm filter showed selectivity for some nitrogen-containing compounds. 

The response of phosphorus in the FPD was determined to be linear while that of sulfur varied such that the square root of the response was proportional to concentration. This prompted researchers to propose a mechanism in which S2 was formed and was the chemiluminescent species. The following mechanism has been proposed (28) ... 

Nature of the Chemiluminescence.—Many observations lead to the conclusion that the glow is produced by the combination of gases only. The glowing zone may be removed from the surface of the phosphorus by a current of air, leaving a dark space in the immediate neighbourhood of the phosphorus.1... 

It has been shown by numerous investigators that the connection between ionisation, oxidation and chemiluminescence is a close one. If air or oxygen is mixed with the vapours of turpentine, etc., the conductivity of the mixture after passing over the phosphorus is only slight, corresponding to the suppression of the glow.4... 

The Glow of Phosphorus—Effect of Pressure upon Oxidation of Phosphorus— Velocity of the Reaction—Effect of Temperature—Production of Ozone— Inhibition of the Glow—Nature of the Chemiluminescence—Ionisation by the Glow—The Emission Spectrum. 

Anion-radicals were obtained by alkali-metal reduction of phospholes in ether solvents.602 Sodium and potassium gave radicals rapidly whereas lithium failed. The radicals persisted several days at — 80° but decomposed above - 30°. The persistence of the radicals and their relatively large phosphorus hyperfine splitting, e.g., 186, by comparison with anion-radicals from phosphines, were interpreted in terms of aromatic character.602 The results obtained here contrast with results obtained earlier for 187 where phenyl cleavage and small phosphine-like phosphorus splittings had been observed for the products of attempted anion-radical formation.603 Chemiluminescence on oxidation of the anion-radical of 1,2,5-triphenylphosphole has been reported.604... 

The lower glow limit was apparently first examined in detail by Chariton and Walta ", who found the oxidation of phosphorus was accompanied by chemiluminescence if a certain critical pressure of O2 (dependent on temperature and surface effects) was exceeded. The addition of Ar diminished the critical pressure and light yield. Bodenstein criticized the claim of Chariton and Walta that oxidation... 

Kowalsky reported that the oxidation of phosphorus vapor occurred only between certain upper and lower limits of O2 pressure. At the lower limit [02]i varied inversely with the phosphorus pressure. The upper pressure limit was independent of T between —40 and +15° C, with [Ozh about 4 x 10" [P4]. Between the lower and upper critical pressures oxidation occurred and was accompanied by chemiluminescence. The results were interpreted in terms of Semenov s theory of branched-chain reactions. ° ° . Kowalsky s experimental work was consistent with eqn. (c) and Semenov himself discarded eqn (b). 

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