Exploring inhibition of chemiluminescence mechanisms with fluorescence quenching studies and interaction energy calculations

Authors : Zhenbo LIU, Tangmi YUAN, Yongming LIU, Wenzuo LI, Qingzhong LI, BO XIAO, Jianbo CHENG

Pages : 1566-1576

View : 10 | Download : 5

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Carbamates weaken the luminol-H$_{2}$O$_{2}$ chemiluminescence insert ignore into journalissuearticles values(CL); catalyzed by sodium copper chlorophyll insert ignore into journalissuearticles values(SCC);. The capacity to inhibit the CL of three carbamates is in the order of carbaryl insert ignore into journalissuearticles values(CBL); \textgreater carbofuran insert ignore into journalissuearticles values(CBF); \textgreater metolcarb insert ignore into journalissuearticles values(MTC);. Mechanisms of carbamates inhibiting SCC-luminol-H$_{2}$O$_{2}$ CL are investigated using fluorescence quenching and quantum chemistry simulations for the first time in this work. Carbamate-SCC interactions studied using fluorescence spectroscopy show that with the increasing concentration of the SCC, the fluorescence of carbamate is quenched regularly, and the quenching mechanism is a static quenching process. Binding constants insert ignore into journalissuearticles values($K_{B});$ of the three carbamates with SCC are CBL insert ignore into journalissuearticles values(4.39 x 10$^{5});$ > CBF insert ignore into journalissuearticles values(1.46 x 10$^{4});$ > MTC insert ignore into journalissuearticles values(2.16 x 10$^{3}$ L/mol);, which is completely harmonious with the capacity to inhibit CL of the carbamates. Furthermore, the carbamate-SCC interaction energies from quantum chemistry simulations are CBL-porphyrin copper insert ignore into journalissuearticles values(PPCu); insert ignore into journalissuearticles values(-30.1);, CBF-PPCu insert ignore into journalissuearticles values(-21.0);, and MTC-PPCu insert ignore into journalissuearticles values(-19.9 kJ/mol);, which is also identical to their inhibiting capacity. This provides further evidence that the formation of carbamate-SCC complexes reduces the SCC catalytic activity and the CL intensity decreases. In addition, a novel flow injection chemiluminescence method for the determination of carbamate was established based on carbamate inhibiting CL of the SCC-luminol-H$_{2}$O$_{2}$ CL system under alkaline conditions. This work may contribute to the study of the mechanism of CL inhibition using fluorescence quenching and quantum chemistry calculation methods.
Keywords : Chemiluminescence, carbamate SCC interactions, fluorescence quenching, quantum chemistry calculation