Dysprosium fluorescence

Different lanthanide metals also produce different emission spectrums and different intensities of luminescence at their emission maximums. Therefore, the relative sensitivity of time-resolved fluorescence also is dependent on the particular lanthanide element complexed in the chelate. The most popular metals along with the order of brightness for lanthanide chelate fluorescence are europium(III) > terbium(III) > samarium(III) > dysprosium(III). For instance, Huhtinen et al. (2005) found that lanthanide chelate nanoparticles used in the detection of human prostate antigen produced relative signals for detection using europium, terbium, samarium, and dysprosium of approximately 1.0 0.67 0.16 0.01, respectively. The emission... 

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. 

There are not many uses for dysprosium. Scientists continue to experiment with it as a possible alloy metal (it has a high melting point) to be mixed with steel to make control rods that absorb neutrons in nuclear reactors. There are only a few commercial uses for dysprosium, such as a laser material and as a fluorescence activator for the phosphors used to produce the colors in the older TV and computer cathode ray tubes (CRTs). When combined with steel or nickel as an alloy, it makes strong magnets. 

Dysprosium is used in nuclear reactor fuels to measure neutron flux. It also is used as a fluorescence activator in phosphors. 

Of the other lanthanides, europium(III) chloride, an / ion, and terbium(III) chloride, an / ion, have been reported to fluoresce weakly in dimethylformamide solution [16]. The chloride and sulfate salts of samarium(III), an / ion, of gado-linium(III), an f" ion, and of dysprosium(III), an/ ion, are also reported to luminesce weakly in solution [16]. All five of these lanthanides give rise to weak lines which have been assigned to/->-/transitions. 

Let us now leap forward in time to be able to close the matter of the division of erbium. Lecoq de Boisbaudran developed a fantastically intricate and wearisome method for the separation of gadolinite rare earth elements, consisting of 32 precipitations with ammonia and 26 subsequent precipitations with oxalate, separation of the fractions and their spectroscopic and fluorescence studies. In 1886, he came to the conclusion that holmium is not homogeneous either, it contains another element which he named dysprosium. This element was apparently accepted by the chemists of the world without the usual unbelief and debate (Lecoq de Boisbaudran 1886). 

Dysprosium tungstate fluoresces when irradiated with u.v, light (280 nm). 

Procedure. 0.005 ml of the test solution is transferred to a Whatman No. 1 filter paper by micropipette. After quickly drying the spot in hot air, the paper is sprayed with a 15 % solution of sodium tungstate and examined under u.v. light. A whitish-pink fluorescence indicates the presence of dysprosium. 

Of the rare earths, samarium and europium interfere, both giving a red fluorescence under the conditions described. The test is a useful one for identifying dysprosium on paper chromatograms. 

Procedure. Using the method given for dysprosium (see page 401), a red fluorescence indicates the presence of europium or samarium. When the paper is heated to 80° C, the fluorescence due to europium remains unchanged while that of samarium becomes orange. 

Salts of some of the rare earths form fluorescent complexes with 8-hydroxy-quinoline. Yttrium and lutetium show a yellow-green fluorescence and lanthanum a green fluorescence. With oxine, gadolinium gives a deep brown fluorescent complex. Cerium, praseodymium, neodymium, samarium, terbium, dysprosium, erbium, thulium, and ytterbium do not form fluorescent oxinates. 

Fig. 37D.I1. Analytical curve for the X-ray fluorescence determination of holmium in a holmiuin-dysprosium mixture.

Rare-earth metals are of great importance in modem society because of their widespread applications in high-tech industries. Neodymium (Nd) and dysprosium (Dy), for instance, are especially indispensable in the manufacture of permanent magnets, which are essential to the generators and motors of wind turbines and electric vehicles. Other rare-earth metals such as yttrium (Y) and europium (Eu) are extensively used as fluorescent materials for lamps and TV displays [1]. In recent years, industrial wastes and scrap such as a spent TV display, fluorescent lamps, and permanent magnets have been recognized as valuable secondary resources of critical metals [2-4-]. 

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