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The Chemiluminescence of Pyrogallol

reaction, light-production, oxidation and light

THE CHEMILUMINESCENCE OF PYROGALLOL It has been known for a long time that pyrogallol takes up oxygen from the air in presence of alkali and is converted into brown oxidation products of unknown composition. The depth of brown coloration (and consequently the extent of oxidation) depends on the concentration of alkali added. I have never under any conditions obtained light during this oxidation, although concentrations of alkali ranging from n to n/6,000 NaOH, both with and without have been used. It has also been long known that pyrogallol will turn brown with and some oxidizing enzyme from organisms. Purpurogallin, a sub stance of doubtful composition ?), is said to be formed and the reaction has been used in studying oxidizing enzymes quantitatively. Only if be present will this reaction produce light. It is similar to the oxidation of gum guaiac to guaiacum blue, but I find that guaia cum blue can be formed under many conditions when pyrogallol can not be oxidized with light-production. Thus hydrogen peroxide is necessary for light-production, even when potato-juice is used as the oxidase solution—i. e., even when a juice is used containing an oxidase which will oxidize guaiac tincture directly (without addition of It is then strictly a peroxidase which is responsible.' Blood also gives the reaction if is present. Catalase takes no part, and may be destroyed by heating the potato-juice to 60r.

Thinking that this reaction might throw some light on lumin escence in organisms, I have studied it in some detail, with especial reference to the substances which are known to affect light-production in organisms. It is the oxidases, similar to those which blue guaia,c,

that are concerned in the light-production of pyrogallol and potato juice, but, as we shall see, many inorganic catalyses are also able to oxidize pyrogallol with light-production. It may be noted in passing that although light can be produced at 0° C., a considerable amount of heat is given off, and in this respect the oxidation differs markedly from those giving light in organisms.

In studying the reaction I have used mostly pure potato-juice (i. e., the pressed, unfiltered extract of grated potatoes, strained through cheese-cloth and decanted from the starch-grains) or a 1 per cent ox blood extract (i. e., 1 gram of dried defibrinated ox blood to 99 parts water) added to an equal volume of a half-and-half mixture of m/100 pyrogallol and 3 per cent (Merck's perhydrol). The experiments will be given in the form of tables or data under the following heads: 1. Concentration of the three substances necessary for light-production.

2. Substances taking the place of blood or potato oxidase, pyrogallol, and 3. Effect of temperature on the reaction.

4. Effect of KCN, NaOH, and HC1.

5. Effect of fat-solvent anesthetics.

6. Is the oxidase a catalyser?