Europium determination

Further studies of level structures of nuclei also showed a special behaviour of rotational levels, which indicated that nuclei might be deformed. Actually, the existence of deformed nuclei was realized already in 1935 by Schuler and Schmidt [28] who, from optical hyperfine structure investigations of europium, determined the spectroscopic quadrupole moments for Eu and Eu to be... 

APPLICATION OF EUROPIUM-SENSITIZED LUMINESCENCE FOR POST-COLUMN DETERMINATION OF OXYTETRACYCLINE IN BOVINE MILK... 

SPECTROFLUORIMETRIC DETERMINATION OF OXYTETRACYCLINE AND CITRATE ION USING TERNARY COMPLEX WITH EUROPIUM(III)... 

For the determination of the enantiomeric excess. 23 mg of the mi-hydroxy ester (containing 2 5% //-product) and 9 mg of tris[3-(heptafluoropropylhydroxymethylene)-a-camphorato]europium are dissolved in 0.5 mL of CDC13. The ec is calculated from the peak heights and areas of the resolved doublets, due to the methyl groups attached to C-2. of the minor (f) 1.74) and major (<5 1.98) enantiomers. 

The enantiomeric purity of optically active sulphoxides can be determined by chiral lanthanide shift reagents such as tris(3-trifluoroacetyl-ti-camphorato)europium(III) and tris(heptafluorobutyryl-d-camphorato)europium(III)218-219-221, the latter shown in Scheme 23. 

The relative amounts of sodium alkenesulfonate isomers and sodium hydroxyalkanesulfonate isomers have been determined with 1.19-2.07% precision by NMR measurements of the methyl signals of methyl esters in carbon tetrachloromethane with 1.3 mol equivalent tris(heptafluorobutanoylvivaloyl-methanato)europium(I) and tri(dipaloylmethanato)europium as shift reagent. The... 

A closely related method does not require conversion of enantiomers to diastereomers but relies on the fact that (in principle, at least) enantiomers have different NMR spectra in a chiral solvent, or when mixed with a chiral molecule (in which case transient diastereomeric species may form). In such cases, the peaks may be separated enough to permit the proportions of enantiomers to be determined from their intensities. Another variation, which gives better results in many cases, is to use an achiral solvent but with the addition of a chiral lanthanide shift reagent such as tris[3-trifiuoroacetyl-Lanthanide shift reagents have the property of spreading NMR peaks of compounds with which they can form coordination compounds, for examples, alcohols, carbonyl compounds, amines, and so on. Chiral lanthanide shift reagents shift the peaks of the two enantiomers of many such compounds to different extents. 

Determined by HPLC or H NMR in the presence of chiral europium (111) tiis[3-(heptafluoro-propylhydroxy- methylene)-(+)-camphorate]... 

The absolute configuration of C-3 of the chromophore 459 of isopyoverdins was determined to be S from the circular dichroism (CD) spectrum (Cotton effect +242 nm, —290 nm, +358 nm) of 460 obtained from isopyoverdin by acidic hydrolysis <2001T1019>. Diorganotin(iv) complexes with 4//-pyrido[l,2-/z pyrimidin-4-ones 461 <1996AOM47>, complexes of 2-methyl- and 2-methyl-8-nitro-9-hydroxy-4//-pyrido[l,2-tf]pyrimidin-4-ones with Ag(i), Cu(ll), Ni(n), Co(n), and Mn(n) ions <2000RJD587>, 2,4-dimethyl-9-hydroxypyrido[l,2-tf]pyrimidinium perchlorate and its complexes with prasedynium, neodymium, samarium, and europium <2000RJD310> were characterized by UV spectroscopy. 

Iieser et al. [628] studied the application of neutron activation analysis to the determination of trace elements in seawater. The rare earths included in this study were cerium and europium. The element concerned were adsorbed onto charcoal. Between 75% and 100% of the elements were adsorbed onto the charcoal which was then subjected to analysis by neutron activation analysis. Cerium (300 p,g/l) and europium (0.00082 pg/1) were found in North Sea water by this method. 

Other analytes recently determined by means of immobilized biolumines-cent enzymes are europium(III) [232], d- and L-lactate in beer [233], and d-sorbitol [234], A novel approach of the sensing layer design was reported for... 

EXAFS study on Eu2+ and Sr2+ in both solid state and aqueous solution gave coordination numbers of 8.0 for strontium(II) and 7.2 for europium(II) (228). The water exchange rate measured on the divalent europium aqua ion is the fastest ever measured by 170 NMR (Table XVI) (2). The activation volume is much more negative (—11.7 cm3 mol-1) than those determined on trivalent lanthanide aqua ions clearly indicating an a-activation mechanism which is most probably a limiting... 

Example Fluoride-ion Electrode In this particular instance the membrane essentially comprises of a single crystal of lanthanum fluoride (LaF3), usually doped with a slight trace of europium (II), Eu2+, so as to initiate the crystal defects required for establishing its electrical conductivity. Therefore, the potential developed at each surface of the membrane is finally determined by the exact status of the equilibrium ... 

Time-resolved approaches for multi-analyte immunoassays have been described recently. Simultaneous determination of LH, follicle stimulating hormone (FSH), hCG, and prolactin (PRL) in a multisite manual strip format has been reported. 88 Four microtiter wells are attached to a plastic strip, two-by-two and back-to-back, such that the wells can be read on a microtiter plate reader. In a quadruple-label format, the simultaneous quantitative determination of four analytes in dried blood spots can be done using europium, samarium, dysprosium, and terbium. 89 In this approach, thyroid-stimulating hormone, 17-a-hydroxyprogesterone, immunoreactive trypsin, and creatine kinase MM (CK-MM) isoenzyme are determined from dried blood samples spotted on filter paper in a microtiter well coated with a mixture of antibodies. Dissociative fluorescence enhancement of the four ions using cofluorescence-based enhancement solutions enables the time-resolved fluorescence of each ion to be measured through four narrow-band interference filters. 

Similar differentiation between enantiomers by means of NMR can also be achieved by the use of chiral lanthanide shift reagents (243). Tris-[3-(heptafluoropropylhydroxymethylene)-d-camphorato] -europium was used for the first time (244) for determining the enantiomeric content of benzyl methyl sulfoxide 34. The enantiomeric composition of the partially resolved methyl p-tolyl sulfoxide 41 was estimated using tris-[3-(r-butylhydroxymethylene)-c -camphorato]-europium (245). Another complex of europium, tris-[3-(trifluoro-methylhydroxymethylene)-c -camphorato] europium (TFMC), in contrast to those mentioned above, was effective in the differentiation of various enantiomeric mixtures of chiral sulfinates (107), thiosul-finates (35), and sulfinamides (246). 

Samarium - the atomic number is 62 and the chemical symbol is Sm. The name derives from the mineral Samarskite, in which it was found and which had been named for Colonel von Samarski , a Russian mine official. It was originally discovered in 1878 by the Swiss chemist Marc Delafontaine, who called it decipium. It was also discovered by the French chemist Paul-Emile Lecoq de Boisbaudran in 1879. In 1881, Delafontaine determined that his decipium could be resolved into two elements, one of which was identical to Boisbaudran s samarium. In 1901, the French chemist Eugene-Anatole Demar9ay showed that this samarium earth also contained europium. 

Ion-exchange reactions were used for the accumulation of europium(III) [158] and iron(III) [159] ions on the surface of GCE coated with Nafion , and chromium(VI) ions on the surface of GCE covered by a pyridine-functionalized sol-gel film [160], which were combined with the stripping SWV Furthermore, a cathodic stripping SWV was used for the determination of sulfide [161,162], thiols [163-166], selenium(lV) [167-170], halides [171-173] and arsenic [174] accumulated on the snrface of mercury electrode. 

After the discovery of plutoninm and before elements 95 and 96 were discovered, their existence and properties were predicted. Additionally, chemical and physical properties were predicted to be homologous (similar) to europium (gjEu) and gadolinium ( Gd), located in the rare-earth lanthanide series just above americium (gjAm) and curium ((,jCm) on the periodic table. Once discovered, it was determined that curium is a silvery-white, heavy metal that is chemically more reactive than americium with properties similar to uranium and plutonium. Its melting point is 1,345°C, its boihng point is 1,300°C, and its density is 13.51g/cm. ... 

The use of chiral shift reagents, e.g. tris-[3-(trifluoromethyl)- or -(hepta-fluoropropyl)-hydroxymethylene)-d-camphorato)]europium, praseodymium, or ytterbium, in the determination of optical purities of chiral alcohols, ketones, esters, epoxides, amines, or sulphoxides, or in the separation of n.m.r. signals of internally enantiotopic protons e.g. PhCHjOH), has been described. 

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