Premium
(Tetracycline)europium(III) Complex as Luminescent Probe for Hydrogen Peroxide Detection
Author(s) -
Dehaen Geert,
Absillis Gregory,
Driesen Kris,
Binnemans Koen,
ParacVogt Tatjana N.
Publication year - 2009
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200900184
Subject(s) - chemistry , europium , hydrogen peroxide , molybdate , luminescence , aqueous solution , analytical chemistry (journal) , ion , molar concentration , ligand (biochemistry) , inorganic chemistry , crystallography , nuclear chemistry , chromatography , organic chemistry , biochemistry , physics , receptor , optoelectronics
Luminescence spectra of aqueous solutions containing a fixed concentration of tetracycline (TC) and increasing concentrations of Eu 3+ were recorded both in the absence and presence of hydrogen peroxide (H 2 O 2 ). In H 2 O 2 ‐free solutions in which the Eu/TC molar ratio was varied from 1 : 1 to 8 : 1, the 5 D 0 → 7 F 0 transition consisted of only one peak at 580 nm. In the presence of H 2 O 2 , an extra peak appeared in the spectrum at 578 nm when the Eu/TC molar ratios were above 2.5. A detailed analysis of this spectral region revealed that at lower Eu/TC molar ratios (up to 2 : 1), the 5 D 0 → 7 F 0 transition experienced a slight blue shift. This indicates that at low Eu/TC molar ratios, the presence of H 2 O 2 leads to two different environments of the trivalent europium ions, which most likely form bridged peroxide complexes with hydrogen peroxide ( μ ‐H 2 O 2 ligand). Luminescence spectra measured in the presence of molybdate ions, which catalytically decompose H 2 O 2 , led to the disappearance of the extra europium(III) site that was formed in the presence of H 2 O 2 . The intensity of the hypersensitive 5 D 0 → 7 F 2 transition did not linearly depend on the H 2 O 2 /TC molar ratio. For H 2 O 2 /TC ratios up to 10, a sharp linear increase of the peak intensity was observed, but with further increase of the H 2 O 2 concentration, the intensity remained nearly constant. For H 2 O 2 /TC ratios above 100, the intensity of this transition even started to decrease, which limits the use of the (tetracycline)europium(III) system to quantify hydrogen peroxide in solution.