Luminol Based Chemiluminescence

Luminol-based chemiluminescence methods have also been employed for detection of analytes in flowing stream analytical techniques such capillary electrophoresis (282), flow injection analyses, and hplc (267). AppHcations of the enhanced luminol methodology to replace radioassay methods have been developed for a number of immunological labeling techniques (121,283). 

DPA) in dimethylphthalate at about 70°, yields a relatively strong blue Umax =435 nm) chemiluminescence the quantum yield is about 7% that of luminol 64>. The emission spectrum matches that of DPA fluorescence so that the available excitation energy is more than 70 kcal/mole. Energy transfer was observed on other fluorescers, e.g. rubrene and fluorescein. The mechansim of the phthaloyl peroxide/fluorescer chemiluminescence reaction very probably involves radicals. Luminol also chemiluminesces when heated with phthaloyl peroxide but only in the presence of base, which suggests another mechanism. The products of phthaloyl peroxide thermolysis are carbon dioxide, benzoic acid, phthalic anhydride, o-phenyl benzoic acid and some other compounds 65>66>. It is not yet known which of them is the key intermediate which transfers its excitation energy to the fluorescer. 

Lei et al. and Nie et al. [110, 111] have reported two assays for indapamide and indomethacin, respectively, also based on luminol as chemiluminescent reagent. Again MAA and EGDMA were used as monomers and acetonitrile as porogen. Excellent detection limits were achieved 10 x M for indapamide and indomethacin in urine and 10-9 M for epinephrine in serum. The authors describe the crossreactivity for other contaminants potentially present in urine such as antibiotics (norfloxacin), ions (Fe2+, Ca2+, K+), or glucose. 

A Novel Synergistic Enhancer for HRP-Luminol-H 2 O2 Based Chemiluminescence 267... 

Some work has been done with fiber-optic-based chemiluminescence sensors. Luminol has been used with various enzymes immobilized on the end of an optical fiber. Sensors based on electrogenerated chemiluminescence with luminol or tris(2,2 -bipyridyl)ruthenium(II) have appeared the latter is particularly attractive due the regenerable nature of the reagent. Importantly, for these applications of liquid-phase chemiluminescence, the reactions are occurring at a reactive surface rather than in a homogeneous solution and as such mass transfer probably controls the overall response. 

Figure 27.3 Chemiluminescence of luminol. The chemiluminescence technique is based on generating free oxygen radicals (HO, 02, O2, ROO ) in a luminescence system. The luminol (LH2)-hydrogen peroxide system in alkaline solution leads to aminophtalated anion in an excited electronic state, a compound that when de-excited emits a quantum of light (a band with maximum at 430 nm).

Indirect determination of AA based on the suppression of luminol/ KIO4 chemiluminescence system 0.06 No data 1.0 Pharmaceuticals 1999 115... 

Indirect determination based on quenching of the titanium-luminol complex chemiluminescence caused by adding AA 5.7 515 No data Pharmaceuticals 2009 131... 

CHEMILUMINESCENT ANALYSIS BASED ON THE LUMINOL OXIDATION REACTION IN SPECIFIC REGIMES... 

Freeman T.M., Seitz W.R., Chemiluminescence fiber optic probe for hydrogen peroxide based on the luminol reaction, Anal. Chem. 1978 50(9) 1242-1246. 

Abdel-Latif M.S., Guilbault G.G., Peroxide optrode based on micellar-mediated chemiluminescence reaction of luminol, zlna/. Chim. Acta 1989 221 11-17. 

The photosensitized results are from I.B.C. Matheson and J. Lee 118h It is seen that the quantum yields in photosensitized oxidation depend on the concentrations of luminol and base, and on temperature. At higher temperature (50°) and low luminol concentrations, the quantum yields reached those of hemin-catalyzed hydrogen peroxide oxidation of luminol in aqueous-alkaline solution. Primary products of the photosensitized oxidation are singlet oxygen (1Ag02) or a photoperoxide derived from methylene blue, but neither of these is directly responsible for the luminol chemiluminescence. 

Here A and B are non-luminescence molecules. The C is the excited state of the product C. Often these reactions involve oxidation reactions and the presence of a catalyst. Both chemical and biochemical reactions could generate the photon. The intensity of the photons are collected through optical fibers and measured with a photon detector. The most successful chemiluminescence sensor for the detection of the hydrogen peroxide [13] is based on luminol using ferricyanide as catalyst... 

---