Chemiluminescent reaction of fluorescent organic compounds with KHSO5 using cobalt(II) as catalyst and its first application to molecular imprinting
The decomposition of peroxomonosulfate (HSO5-) has been investigated by chemiluminescence (CL). A weak CL was observed during mixing the HSO5- solution with the Co2+ solution in unbuffered conditions. An appropriate amount of fluorescent organic compounds (FOCs), such as dansyl amino acids and pyrene, was added to the KHSO5/Co2+ solution, a strong CL was recorded. A possible CL mechanism, based on studies of the fluorescence, CL, and UV-visible spectra and comparison of Co3+ oxidation ability with the SO4.- radical ion, was discussed. The CL from HSO5-/Co2+ is the emission of singlet oxygen produced from the catalytic decomposition of HSO5-. It was suggested that the decomposition of HSO5- in aqueous solution with Co2+ proceeds via one-electron transfer to yield SO4.- radical ion. The FOC was attacked by SO4.- radical ion and oxidized to decompose into small molecules. During this proceeding, CL emission was given out. The present CL system has been developed as a flow injection analysis for FOCs. The detection limits (S/N = 3) were in the concentration range 10(-9)-10(-7) M for FOCs. Oxidation decomposition and CL emission of the analytes have been used in the molecular imprinting recognition. As an initial attempt, dansyl-L-phenylalanine was used as a template molecule and methacrylic acid and 2-vinylpyridine were used as functional monomers. The network copolymer imprinted with dansyl-L-phenylalanine exhibits an affinity for the template molecule. When the flowing streams of HSO5- and Co2+ solutions mixing through the molecularly imprinted polymer particles filled the flow cell, the template molecule, dansyl-L-phenylalanine reacted with the HSO5-/Co2+ solution and CL was emitted. The dansyl-L-phenylalanine was decomposed during the CL process, and the cavities of a defined shape and an arrangement of functional groups complementary to the template in the polymer were left for the next sample analysis.
Lin
JM
Department of Applied Chemistry, Graduate School of Engineering, Tokyo Metropolitan University, Japan. lin@ecomp.metro-u.ac.jp
Yamada
M