Thallium, fluorescence

Perez Ruiz et al. [26] determined penicillamine and tiopronin in pharmaceutical preparations by flow injection fluorimetry. The procedure is based on the oxidation of these drugs by thallium(III), whereupon the fluorescence of T1(T) produced in the oxidation of penicillamine is monitored using excitation at 227 nm and emission at 419 nm. A linear calibration graph for penicillamine was obtained between 3 x 10-7 and 8 x 10 5 6 M. 

Haapakka and Kankare have studied this phenomenon and used it to determine various analytes that are active at the electrode surface [44-46], Some metal ions have been shown to catalyze ECL at oxide-covered aluminum electrodes during the reduction of hydrogen peroxide in particular. These include mercu-ry(I), mercury(II), copper(II), silver , and thallium , the latter determined to a detection limit of <10 10 M. The emission is enhanced by organic compounds that are themselves fluorescent or that form fluorescent chelates with the aluminum ion. Both salicylic acid and micelle solubilized polyaromatic hydrocarbons have been determined in this way to a limit of detection in the order of 10 8M. 

Robertson, B. and Knox, R.J. (2004) A thallium-sensitive, fluorescence-based assay for detecting and characterizing potassium channel modulators in mammalian cells. Journal of Biomolecular Screening, 9, 671-677. 

Rose, H. J., and Flanagan, F. J., X-ray fluorescence determination of thallium in manganese ores. "U. S. Geological Survey Professional Paper A50-B," 1962, 80-82. 

The mercury photosensitized fluorescence of thallium vapour appears to provide an exception to the rule, because the reaction with the largest cross-section corresponds to a substantial change in internal energy, notwithstanding the opportunity of electronic energy transfer to a state of almost identical internal energy. At 900 °C the reaction... 

Mansfield, J. M., J. D. Winefordner, and C. Veillon High Sensitivity Determination of Zinc, Cadmium, Mercury, Thallium, Gallium, and Indium by Atomic Fluorescence Flame Spectrometry. Anal. Chem. 37, 1049 (1965). 

Fluorescence.—The majority of platinocyanides fluoresce under the stimulus of ultra-violet light1 or of radium radiations, although some salts show no sign of this property. Magnesium, erbium, yttrium, thallium and uranyl salts are cases in point. 

It is obvious from Table 4.6 that the problem of excitation transfer from mercury to thallium is in a very unsatisfactory state. There is an apparent lack of consistency in the results of Kraulinya et al. (104), whose cross sections for excitation transfer to the 8 2S1/2, 6 2D2/2, and 7 2S1/2 levels in thallium seem to depend on the wavelength of the observed fluorescent component. The results of the two groups (Hudson and Curnutte and Kraulinya et al.) do not agree well with each other, and there is no consistent dependence of the measured cross sections on temperature. Finally, one would expect that the cross sections should decrease in some manner with increasing energy gap AE, but the results seem to indicate the opposite. It is manifest that considerable additional experimental work is needed to overcome these difficulties. 

Scintillation counters usually consist of a sodium iodide crystal doped with 1% thallium. The incident X-ray photons cause the crystal to fluoresce producing a flash of light for every photon absorbed. The size of the light pulse is proportional to the energy of the photon and is measured by a photomultiplier. A deficiency associated with scintillation counters is that they do not provide as good energy resolution as proportional or solid state detectors. 

Fluorescent hydrophobes (naphthyl and pyrenyl groups) incorporated into the polysulfobetaines are a powerful tool for studying the formation of intra-and interpolymer aggregates in aqueous and aqueous salt solutions [85,229-231]. Intermacromolecular hydrophobic association is observed as an increase in the excimer emission relative to that of the monomer emission, where h/Iu is the ratio of intensities of excimer and monomer fluorescence which reflects the extent of inter/intra macromolecular interactions. Intramolecular micellization is easily monitored by the quenching efficiency of the thallium ions. The decrease of h/Iu reflects the breaking of the intra- and interchain associations in aqueous salt solutions, leading to chain expansion. 

TJranyl nitrate forms double salts of the type E U02(N03)3, where R =K, NH4, Rb, Cs, or Tl. They may be prepared by crystallising a solution of the mixed nitrates in concentrated nitric acid or by crystallisation from a solution of the alkali uranate in excess of nitric acid. The crystals are all anhydrous, and in the case of the potassium salt are orthorhombic, whilst the rubidium and caesium salts are rhombo-hedral and isomorphous with each other. The ammonium salt yields both orthorhombic and rhombohedral crystals. All exhibit a yellowish-green fluorescence they are liygroscopic and readily decomposed by water into their components. The thallium salt is particularly unstable, being decomposed in moist air. On the other hand, the rubidium salt dissolves in water at 80° C. without decomposition. The corresponding salts of sodium, lithium, or of divalent metals have not been prepared. 

Very elegant experiments unequivocally proving the occurrence of electronic energy transfer were performed in 1922 and 1923 by Carlo and Franck [14], When a mixed vapor of mercury and thallium was irradiated with the mercury line at 253.67 nm, the emission lines of thallium could be observed in addition to the anticipated fluorescence spectrum of mercury. Since thallium cannot absorb 253.67-nm light, it must have been sensitized by the excited mercury atoms in order to produce the green fluorescence... 

The single-cell imaging on microfluidic device helps to quantitatively monitor intracellular sodium ion (Na+) concentration, potassium channel permeability, and apoptosis or necrosis and thus provides an advantage over the patch clamp system [58], The inhibition of potassium channels is monitored by using the FluxOR thallium detection kit. FluxOR dye is cleaved by endogenous esterases to thallium-sensitive fluorescent indicator inside the cells, and... 

Li QY, Rottlander M, Xu MK et al (2011) Identification of novel KCNQ4 openers by a high-throughput fluorescence-based thallium flux assay. Anal Biochem 418(l) 66-72... 

Cavalli P. and Omenetto N. (1990) Optimization of laser excited atomic fluorescence in a graphite furnace for the determination of thallium, Spedrochim Acta, Part B 45 1369-1373. 

Thallium(III), in the form of the TICU or TlBr4" complex ions, reacts in acid media (1-2 M HCl) with the basic xanthene dye, Rhodamine B (formula 4.29), to form a red-violet, slightly fluorescent ion-associate complex, which is soluble in benzene, DIPE, and isoamyl alcohol. These extracts have been used for the spectrophotometric determination of thallium [8]. A mixture of CeHe and CCI4 (2+1) is a convenient extractant since it is denser than water. 

The increasing interest in thallium chemistry is due to several distinct applications. Besides the above-mentioned redox properties used in organic preparative chemistry and for model studies of electron transfer reactions, it can be perceived that thallium has found applications as a model for the general behavior of metal ions. For example, Tr is of particular interest because of its importance as a probe for the role of alkali metal ions. The ionic radius of TL, rxl. = 1.47 A, is only slightly larger than ky. = 1.33 A, and approximately the same as rRb+ = 1.47 A (34). Because of the ease with which Tl can be monitored by spectroscopic (35, 36), fluorescence (57), polarographic... 

I a porphyrins are salts with two M+ counterions II a and II b porphyrins contain metals in their +2 oxidation states Illb porphyrins in the +3 state. All complexes are diamagnetic and produce normal electronic spectra. Most of them fluoresce. For thallium a labile green TPP complex has been described (696, 646, 483, 458), which could be the TI21 salt [.Rothemund (153)]. A report on Tl11 porphyrins (153) is probably in error, because in air only Tlni porphyrins have been found in later investiga-... 

FLUORESCENCE CHARACTERISTICS OF NOVEL CHLOROPHENYL-ARSENOXYLPHENYLAZO RHODANINES AND APPLICATION IN THE DETERMINATION OF THALLIUM (I)... 

All fluorescence measurements were performed with a Perkin-Elmer (USA) Model LS-55 spectrofluorimeter with 1.0 cm quartz cell. The excitation and emission bandwidths were set at 10 nm throughout the experiment. Stock thallium solution (lmg/mL) was prepared by dissolving purified metal thallium. Working standard solutions were freshly prepared by appropriate dilution with doubly distilled demineralized water. 3-(4 -chIorophenyl)-5- (2 -arsenoxyl phenylazo) rhodanine(4ClRAAP) (2 10 4 mol/L) was prepared by dissolving 0.0944 g of the reagent in 1000 mL absolute ethanol. Working solution was freshly prepared by appropriate dilution with doubly distilled demineralized water. 

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