Dye Sensitized Photoöxidation<sup>1</sup>

Oster, Gérald; Bellin, Judith S.; Kimball, Robert W.; Schräder, Malcolm E.

doi:10.1021/ja01528a019

Cited by 105 publications

(31 citation statements)

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“…The results obtained from the photolysis of crystal violet in deoxygenated solutions and in poly(viny1 alcohol) films are consistent with the view that the same species, the semiquinone radical, is formed in both instances. Contrary to previous reports [5][6][7][8] that triphenylmethane dyes do not undergo photoreduction in solution in the presence of a mild reducing agent such as ascorbic acid except when bound to a high-molecularweight polymer, the present results indicate that photobleaching of crystal violet oxalate solutions does occur via a one-electron reduction of the dye cation to the neutral semiquinone radical, which is quite stable in the absence of oxygen but is rapidly destroyed by light of wavelengths in the region of 400 nm. The reducing agent in this case is probably the oxalate anion, although we have shown that photoreduction also occurs in the presence of ascorbic acid by observing the characteristic ESR spectrum of the oxidized ascorbic acid free radical [29] during illumination of the dye [unpublished data].…”

Section: Resultscontrasting

confidence: 88%

Photoreduction of Crystal Violet in Solution and in Poly(vinyl Alcohol) Films

Leaver

1972

Photochem & Photobiology

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Abstract— The photolysis of crystal violet oxalate has been studied in aqueous and non‐aqueous solutions and in films of poly(viny1 alcohol) at room temperature. Evidence has been obtained from electron‐spin‐resonance, absorption and fluorescence spectroscopy for the formation of the semireduced dye radical, tri‐(p‐dimethylaminophenyl)methyl, both in solution and in the solid state. Electron spin resonance and luminescence spectra of the radical produced by electrolytic reduction of the dye are also reported.

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Section: Resultscontrasting

confidence: 88%

Photoreduction of Crystal Violet in Solution and in Poly(vinyl Alcohol) Films

Leaver

1972

Photochem & Photobiology

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“…Therefore, visible light was used with photoactive dyes to scavenge the quenchers of the chemiluminescence system. Singlet oxygen and free radicals are generated from molecular oxygen and photosensitive dye upon light irradiation (5). All five photoactive dyes examined in the present study improved kinetics of HRP-catalysed chemiluminescence when light irradiation of dye was used to pretreat luminol solutions (Fig.…”

Section: Discussionmentioning

confidence: 62%

“…In the second experiment, luminol was irradiated with ultraviolet light before subsequent use in the enhanced HRP chemiluminescence system. The use of ultraviolet light was also expected to create free radicals (5) and eliminate the lag time effect (2). In the third experiment, photoactive dye was included in the luminol solution and exposed to white light before the chemiluminescence reaction in order to react with and consume contaminants.…”

Section: Ntro D U Ctlo Nmentioning

confidence: 99%

Improvements to enhanced horseradish peroxidase detection sensitivity

Motsenbocker

Kondo²

1994

J. Biolumin. Chemilumin.

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At very low horseradish peroxidase (HRP) concentrations, the enhanced chemiluminescence reaction is often characterized by a lag time between initiation of the reaction and beginning of light output. In this study, four treatments of luminol solution were examined in an effort to remove the lag time and to improve chemiluminescence light output. Addition of ammonium persulphate stimulated light output more than tenfold. Ultraviolet irradiation and photoactive dye pretreatment of luminol solution both increased light output fourfold. Luminol purity was the most important factor affecting detection sensitivity. Recrystallization of luminol from base improved the detection limit 13-fold although there was an improvement in the detection limit from 13 attomoles per millilitre to 5 attomoles per millilitre with highly purified luminol when photoactive dye pretreatment was utilized. The results are consistent with a simple interference mechanism whereby enhancer radicals produced by the enzyme are preferentially quenched by contaminants present in the luminol, in the enhancer and in the solvent used to dissolve the enhancer. Consumption of these interferences prior to light emission results in a lag time and a less favourable HRP detection limit.

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“…According to Oster et al (1959) only those dyes which are capable of being photoreduced can act as sensitizers for phtooxidation.…”

Section: Discussionmentioning

confidence: 99%