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[en] The use of a flow through solid phase terbium-sensitized luminescence system is described for the determination of the widely used fluoroquinolone norfloxacin. A chelate between the terbium ion and the analyte is formed online previously to the sample injection into the carrier stream. Then the chelate is transported towards the flow-through cell, where it is retained on a cationic Sephadex resin packed in the cell, developing the corresponding luminescence signal. Afterwards, an ethylenediaminetetraacetic acid solution was used as eluting agent, in order to regenerate the sensing zone. The system has been satisfactorily applied to the determination of norfloxacin in human urine and serum, without the need of a pre-treatment. The response was linear in the range 10-150 ng ml-1. The detection and quantification limits were 1.5 and 5 ng ml-1, respectively and the R.S.D. 1.82%
[en] The reactivities of lanthanide ions in their excited states are first considered in water and the energy diagrams of most important of them are sketched to illustrate the highly oxidizing and reducing species involved reacting with one-electron steps. Anomalous photoluminescence behavior of Tb(III) chelated by 2,6-bis[N,N-bis(carboxymethyl)aminomethyl]-4-benzoylphenol is studied. The present chelate is known to show relative strong chemiluminescence in the presence of hydrated electron and oxidizing radicals but it shows an extraordinarily short luminescence lifetime of radiative relaxation of its 5D4 state under photoexcitation.
[en] Undoped, Tb3+- and Eu3+-doped ZnGa2O4 colloidal nanocrystals were synthesized by a nonhydrolytic hot solution chemistry. Undoped nanocrystals exhibited an intrinsic blue emission peaking at 437 nm by self-activated transition. The emissions of Tb3+-and Eu3+-doped ZnGa2O4 nanocrystals consisted of their own characteristic green and red line peaks (5D4-7Fj transitions), respectively. Synthetic parameters such as activator concentration and reaction time were varied to investigate their effects on luminescent properties. Tb3+-doped colloidal nanocrystals synthesized for a short reaction time showed an unprecedented, exclusively green luminescence with the host blue emission effectively suppressed. On the other hand, the emission of Eu3+-doped ones was weak with the host emission persistently present regardless of reaction time.
[en] The SiO2: Tb, Yb inverse opals with photonic band gap at 465 or 543 nm were prepared, and an effect of photonic band gap on upconversion spontaneous emission from Tb3+ was investigated. The results show that the photonic band gap has a significant influence on the upconversion emission of the SiO2: Tb, Yb inverse opals. The upconversion luminescence of the Tb3+ ions is suppressed in the inverse opal compared with the luminescence of that of the reference sample. - Highlights: ► Upconversion emission from Tb3+ was observed in the SiO2: Tb, Yb inverse opal. ► UC emission of Tb3+ was modulated by controlling the structure of inverse opal. ► UC emission of Tb3+ was depressed in the inverse opal.
[en] Bismuth tellurite Bi2TeO5 (BTO) is a photorefractive crystal with special capability of self-fixing hologram recording. Single crystals of BTO:Tb were grown by the Czochralski technique. Five infrared transitions were identified and analyzed in the high resolution absorption spectra from the 7F6 ground state to the 7F4, 7F3, 7F2, 7F1, and 7F0 manifolds together with their Stark components. The features of the Tb3+ transitions are in accordance with the single site Tb substitution to one of the slightly different Bi-site.
[en] In this work, a new ligand, 2,9-bis [N,N-bis(carboxymethyl)-aminomethyl]-1,10-phenanthroline (BBCAP), was synthesized and used to establish a novel fluorimetric method for the determination of trace amounts of terbium in a binary system. Its luminescence mechanism was studied. The excitation and emission wavelengths are 284 nm and 547 nm, respectively. Other rare-earth metal ions in 100-fold excess caused no interference. The fluorescence intensity was a linear function of the concentration of terbium in the range of 5.0 x 10-10-1.0 x 10-6 mol/L. The detection limit was 2.0 x 10-11 mol/L (n = 12). The standard addition method was used to determine the terbium in a synthetic rare-earth sample with satisfactory results. This method represents a direct, rapid, selective and sensitive analytical procedure with a widely linear range. (author)