The influence of dioxygen on luminol chemiluminescence

Abstract

Assays of peroxy compounds are commonly performed after chromatographic separation of analysed mixtures. In high-performance liquid chromatography (HPLC), solvent reservoirs are sparged by helium or inline vacuum-degassed in order to control the compressibility of the solvents for efficient pumping. In this study, we investigated the influence of degassing the reaction solution on the light output of the hemin-catalyzed luminol oxidation by various oxidants. We found that, when t-butyl hydroperoxide, hydrogen peroxide, n-butyl hydroperoxide, iodosobenzene and iodobenzene diacetate were used as oxidants, the luminol chemiluminescence was lowered by 50-70% compared with an equilibrated and degassed solution. The opposite effect was observed when dibenzoyl peroxide and 3-chloroperoxybenzoic acid were used as oxidants, as the chemiluminescence increased by approximately 20-30%. The reduced chemiluminescence was explained based on the known role of dioxygen in luminol chemiluminescence. The enhancement of chemiluminescence was rationalized by suggesting an alternative mechanism of luminol oxidation valid for peroxyacids and diacyl peroxides in which the reaction of a peroxyacid anion with the diazaquinone led to light emission with a higher quantum yield than the usual path, which is suppressed by the removal of dioxygen from the reaction solution.

A review of analytical methods measuring lipid oxidation status in foods: a challenging task

“…Baj et al [97] discovered that partial exclusion of oxygen from the reaction medium strongly influenced the light intensity of the luminol reaction, and the effect is dependent on the oxidant analyzed, so an alternative mechanism was suggested for some oxidant species.…”

Chemiluminescence of 5-(azo-para-phenylene-N-aza-15-crown-5)-phthalhydrazide

“…Following Merényi and coworkers, 13,27,28 it is generally accepted [29][30][31] that the CL of luminol starts with electron transfer processes between redox couples. 32,33 By analogy with luminol, we assume that 1 is first dehydrogenated, allowing it then to add a nucleophilic hydroperoxide anion, and then to release a dinitrogen molecule leaving an excited phthalic acid derivative responsible for emitting a photon.…”

A kinetic treatment of stopped‐flow time courses for multiple chemiluminescence of the KIO4‐luminol‐Mn2+ system

“…Alternatively, more than one CL pathway can coexist in the same system. Baj et al (2009) reported that dioxygen could either quench or enhance luminol CL depending on the oxidant used (20). Quenching of CL emission was attributed to the blocking of the CL pathway involving O 2 /O 2 À while blocking of a less efficient CL pathway by certain oxidants caused an increase in CL emissions.…”