A kinetic treatment of stopped-flow time courses for multiple chemiluminescence of the KIO4-luminol-Mn2+ system

ABSTRACT Stopped‐flow time courses for chemiluminescence (CL) of the KIO4‐luminol‐Mn2+system showed an instantaneous jump in initial signal followed by two distinct bands. A kinetic model of the form I=a1⋅e−k1t+a2tn2b2+tn2⋅e−k2t+a3tn3b3+tn3⋅e−k3t with ten adjustable parameters was proposed to account for CL intensity (I) versus time (t) profiles. The three terms in the model represent the three CL bands. Each band was comprised of a rise part and an exponential decay corresponding to the formation and deactivation of the CL emitter. CL bands could have originated from different CL pathways with the participation of reactive species such as O2−, •OH and 1O2 generated in the reactions involving IO4−, O2 and Mn2+. Subsequent reactions of these reactive species with luminol induced CL emissions. Simulation parameters together with peak positions and intensities of the three CL bands were found to vary in different manners by changing conditions such as reagent concentration, pH and temperature. The temperature‐dependence of the rate constants yielded activation energies of 73.2 ± 2.8, 70.1 ± 2.4 and 67.2 ± 1.2 kJ⋅mol‐1 for the three decay processes. Moreover, different substances exhibited a significant influence on the three CL bands and their simulation parameters. The numerous parameters and characteristics of CL emissions could serve as multiple probes for detecting analytes, making this system promising for potential analytical applications. Copyright © 2012 John Wiley & Sons, Ltd.