Chromo-chemodosimetric detection for Fe^(2+) by Fenton reagent-induced chromophore-decolorizing of halogenated phenolsulfonphthalein derivatives

摘要

A commercially-available sulfonphthalein derivative was demonstrated to be a chemodosimeter for Fe2+ and its sensing behavior was further investigated by UV-vis spectroscopy in aqueous media under the optimum conditions.In the presence of chlorophenol red (CPR) and H2O2,the absorption maximum at 435 nm decreased upon addition of Fe2+,resulting in a significant color change of the CPR solution from yellow to colorless.The chemosensor system did not show significant responses to a series of other metal ions including Al3+,Zn2+,Cd2+,Hg2+,Mn2+,Co2+,Fe3+,Ni2+,Cu2+,La3+,Ce4+,Th4+,Pd2+,Pb2+,Sb3+,Cr3+,Au3+,Ag+,Nd3+,Sm3+,alkali and alkaline earth metal cations,allowing for highly selective naked-eye detection of Fe2+.Quantitative analysis was carried out kinetically for practicable the Fe2+ assay when either fixed time method or the initial rate method was applied.When the detecting time was set,the decrease of absorbance signal was linear with Fe2+ concentration in the range of 0 to 7.50 × 10-5 mol L-1 and the regression equation was ΔA = 0.00759 + 0.00593CFe with a correlation coefficient r = 0.9953.The chemodosimetric system has employed an irreversible Fenton reagent-promoted oxidation of the CPR free chromophore and the hydroxyl radicals were generated in the presence of both Fe2+ and hydrogen peroxide.The mechanistic interpretation of the signaling process was partially confirmed by the radical scavenging experiment and the FT-IR analysis of the intermediates formed at different reaction periods.