A fluorescent probe based on isorhamnetin-cyclodextrin inclusion for detecting copper ions was studied. Iso-CD system showed good selectivity and sensitivity for copper ions. When adding copper ions into Iso-CD system, the fluorescent emission intensity of Iso-CD system generated quenching, while other metal ions could not bring obvious change, which meant the Iso-CD system showed good selectivity on copper ions. The fluorescence titration spectra indicated that the concentration of copper ions was inversely proportional to fluorescence intensity, and gave a good linear change in fluorescence emission intensity in response to the concentration of copper ions ranging from 5.0 × 10-8 - 6.0 × 10-6 M. The calibration curve of the relationship between the intensity and copper ions concentration was y = -11.66x +781.13 (R2 = 0.996). The detection limit of copper ions was measured to be 1.7 × 10-8 M. The probable mechanism was studied by UV spectrum and Job's plot method. The results indicated that copper ions could combine with Iso-CD system and Iso-CD-Cu(II) complex formed. The stoichiometric ratio for the complex of Iso and Cu2+ was 2:1. The formation of Iso-CD-Cu(II) complex led to the extension of the conjugated system and the intramolecular charge transfer (ICT) took place, therefore, fluorescence quenching of Iso-CD system occurred. At last, the probe was successfully applied for determination of copper ions in water bodies, vegetables and fruits with good recovery, and the results coincided with that obtained by ICP-AES or AAS methods.

Isorhamnetin-cyclodextrin inclusion: Sensitive fluorescent probe for copper (II)

2019 Fall National Meeting

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