78 KINETICS OF CHEMILUMINESCENCE 



was probably due to lack of suitable light detection equipment and 

 improper choice of concentrations. With the proper concentrations of 

 reagents, it is possible to produce a light visible to the dark-adapted 

 eye. A solution of one gram of luminol per liter of 2N NaOH has been 

 found satisfactory in this connection although other concentrations 

 will also produce light, especially when heated. This reaction between 

 luminol and molecular oxygen has been studied briefly by Sveshnikov 

 (1938), Bernanose et al. (1947), and Bremer (1953). However, the 

 results contained in this paper are the first extensive kinetic studies 

 that have been carried out on this interesting reaction. 



Some qualitative aspects of the reaction involving oxygen and the 

 importance of dissolved oxygen on the emission of light in the case 

 of oxidation by ferricyanide are shown in the following experiment. 



Experimental 



A series of A tubes was arranged as in Fig. 1. The first A tube arm 

 contained a solution of potassium ferricyanide, the second arm con- 



FlG. 1. 



tained a solution of 0.05M luminol in O.IN NaOH. The first arm of 

 the second A tube contained a dilute suspension of luminous bacteria 

 such as A. fischeri or P. phosphoreum^ in a glucose media. The second 

 arm of the second A tube was filled with water. The arm containing 

 luminol was heated to 60° C. A readily visible light was produced by 

 the luminol solution that was about ten times as bright as the lu- 

 minous bacteria. However, when the oxygen was removed by flushing 



* These bacteria were kindly furnished by Dr. Frank Johnson. 



