MECHANISMS OF INHIBITION OF CHEMILUMINESCENCE IN THE OXIDATION OF LUMINOL BY SODIUM-HYPOCHLORITE

Two different mechanisms of inhibition of chemiluminescence in the oxi dation of luminol by sodium hypochlorite were found. Most substances i nvestigated in these experiments acted by scavenging NaOCl. This mecha nism was independent of the concentration of hydrogen peroxide and the incubation time between luminol and inhibitors. The most potent inhib itors were substances containing SH groups. Compounds with amino group s as a target for HOCl/OCl- to yield chloramines were much less effect ive inhibitors. Another mechanism of inhibition was found for catalase . It depended on the presence of hydrogen peroxide in the incubation m edium and the incubation time between luminol and catalase. The enzyme inhibited the luminescence by removing H2O2 at molar concentrations m uch smaller than those found for all other inhibitors. Our results con firm the present models of the mechanism of generation of luminescence in luminol oxidation.