Ozone luminol

The CL reaction of luminol (5-amino-2,3-dihydro-1,4-phthalazinedione) (1) is one of the more commonly used nonenzymatic CL reactions and has been extensively studied [49, 57-59], It is well known that the luminol CL reaction is catalyzed by many kinds of substances, e.g., ozone, halogen-Fe complex, hemin, hemoglobin, persulfate, and oxidized transition metals. The most acceptable scheme is shown in Figure 10. Luminol forms a six-membered ring of peroxide (3) from a diazaquinone intermediate (2) and then, by the decomposition of 3, N2 gas and the Si-excited state of the phthalate dianion are produced, yielding... 

Bacillus subtilis defense mechanism, 610 bovine semm albumin y-radiation, 614 generation inhibition, 612 hydroperoxide synthesis, 315, 320 ludgenin oxidation, 645, 1250-1 luminol oxidation, 643, 644, 1242-4 organic sulfur compounds, 1032-9 ozone water disinfection, 606 peroxynitrite generation, 10, 611-12 Superoxide dismutase (SOD)... 

As an example, a recent intercomparison (37) included three N02 measurement techniques aTDLAS-based system and two chemical-based systems— the photolysis-ozone chemiluminescence system diagramed in Figure 7 and an instrument based on N02 plus luminol chemiluminescence. Above 2 ppbv the three instruments gave similar results, but at sub-ppbv the results from the three techniques became dissimilar. Tests on the prepared mixtures showed that the luminol results were affected by expected interferences from 03 and PAN. No interferences were found in the TDLAS system, but near the detection limit the data analysis procedures calculated levels of N02 that were too high. The outcome of this intercomparison was close to the ideal the sensitivity, specificity, accuracy, and precision of each instrument were objectively analyzed previous data sets taken by different systems can now be reliably evaluated and each investigator was able to perceive areas in which the technique could be improved. 

Difficulties are encountered in determining NO2 using the ozone-chemiluminescence technique due to the non-specific conversion of several nitrogen oxides/oxyacids on the Mo catalyst. Use of FeS04 f°r N02-to-N0 conversion has been described, but humidity-dependent sorption/desorption effects have been reported, e.g., PAN (11). Alternatively, a commercial NO2 analyzer based on surface chemiluminescence of NO2 in the presence of a luminol solution, has been introduced which exhibits the requisite sensitively and selectivity. 

Numerous oxyluminescences, which con be obtained in organic chemistry by rising ozone, open new possibilities for ozone assay, and preliminary results show that a suitable method may be found. Numerical values show the sensitivity of this technique. Small paper disks about the size of confetti and containing no more than 1 y of luminol permit measurements which take only a few minutes. Relatively simple electronic devices permit translation of th se luminescence phenomena into doses (percentages). 

The chemiluminescent hydrazides, especially luminol, produce beautiful luminescence in alkaline solution with ozone [Harvey (15) Briner (9, 10) Druckrey and Richter (14)]-... 

Figure 1. Luminous intensity produced by paper disks treated with luminol and exposed to ozone...

Attempt to Measure Total Quantity of Ozone Produced. In an earlier paper (S) the change of the total amount of light emitted by the oxidation of a certain quantity of luminol by sodium hypochlorite was studied as a function of the pH. For a pH of approximately 10, the reaction is complete and almost instantaneous. The authors attempted to make a dosage with luminol as it was oxidized by ozone after a paper disk was treated with an excess of sodium hypochlorite solution and to measure the light by means of a photometric setup, including a ballistic galvanometer. 

O-NO2) [2], Moreover, ozone and sulfur dioxide have been found to positively interfere with this reaction whereas carbon dioxide negatively. Munemorl et al. [3] discovered that the ozone and sulfur dioxide interference is removed by addition of sodium sulfite (Na2S03) to the luminol solution. Whereas the negative contribution from carbon dioxide can be rectified by adjusting the alkalinity of the solution. 

Gaffney, J. S., Marley, N. A., and Drayton, P. J., Fast gas chromatography with luminol detection for measurement of nitrogen dioxide and PANs, Proceedings Sixth U.S./German Workshop on Ozone/ Fine Particle Science, EPA/600/R-00/076, Riverside, CA, pp. 110-117, 1999. 

Ozone can be determined by its reaction with an adsorbed layer of the dye rhodamine B with a silica gel. Another reaction frequently used in chemical sensors is the reaction of oxygen or hydrogen peroxide with luminol (Fig. 2.21). In combination with enzymatic reactions, highly sensitive and extremely selective sensors can be manufactured. Examples are given in Chap. 8. 

In non-aqueous basic solutions such as DMSO/t-butylate, molecular oxygen alone is sufficient to produce luminol chemiluminescence (cf. p. 102). Reactions producing O2 can be monitored, and a rate of production of 10" moles per second can be recorded [35]. Ozone also produces luminol chemiluminescence [36], but far better results can be obtained using ozone and rhodamine B. 

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