Self-Catalyzing Chemiluminescence of Luminol-Diazonium Ion and Its Application for Catalyst-Free Hydrogen Peroxide Detection and Rat Arthritis Imaging

摘要

We report the unique self-catalyzing chemiluminescence (CL) of luminol-diazonium ion (N-2(+)-luminol) and its analytical potential. Visual CL emission was initially observed when N-2(+)-luminol was subjected to alkaline aqueous H2O2 without the aid of any catalysts. Further experimental investigations found peroxidase-like activity of N-2(+)-luminol on the cleavage of H2O2 into OH center dot radical. Together with other experimental evidence, the CL mechanism is suggested as the activation of N-2(+)-luminol and its dediazotization product 3-hydroxyl luminol by OH center dot radical into corresponding intermediate radicals, and then further oxidation to excited state 3-N-2(+)-phthalic acid and 3-hydroxyphthalic acid, which finally produce 415 nm CL. The self-catalyzing CL of N-2(+)-luminol provides us an opportunity to achieve the attractive catalyst-free CL detection of H2O2. Experiments demonstrated the 10(-8) M level detection sensitivity to H2O2 as well as to glucose or uric acid if presubjected to glucose oxidase or uricase. With the exampled determination of serum glucose and uric acid, N-2(+)-luminol shows its analytical potential for other analytes linking the production or consumption of H2O2. Under physiological condition, N-2(+)-luminol exhibits highly selective and sensitive CL toward O-1(2) among the common reactive oxygen species. This capacity supports the significant application of N-2(+)-luminol for detecting O-1(2) in live animals. By imaging the arthritis in LEW rats, N-2(+)-luminol CL is demonstrated as a potential tool for mapping the inflammation-relevant biological events in a live body.