Enhanced terbium

Figure 9.53 DPA derivatives have been used as potent enhancers of lanthanide luminescence. Three DPA groups can coordinate with a terbium ion. The iodoacetate derivative of DPA has been used to label covalently molecules for lanthanide luminescence.

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. 

The enhancement of the fluorescent yield of terbium, europium, and gadolinium in heavy-water solutions was studied by Kropp and Windsor (105). They observed substantial increases in emission intensities for both terbium and europium compounds when ordinary water was replaced by deuterated water. No appreciable increase was observed for gadolinium, however. For terbium they also obtained the fluorescent lifetimes of the 5D4 state. 

Kleinerman and co-workers (158) reported an enhancement of fluorescent yield of chelated lanthanide ions by Lewis bases. They observed that in liquid, plastic, and glassy solutions containing terbium europium, and samarium chelates, the use of Lewis bases accomplishes the same effect as substituting deuterium for hydrogen. Not all bases, however, are equally effective. The molecular size of the base does not appear to be particularly important, since strong enhancement effects can be obtained with both bulky and small molecules. The nature of the atom of the base having the unshared electron pair is not a determining factor in the enhancement phenomenon. 

Voloshin AI, Shavaleev NM, Kazakov VP. Water enhances photoluminescence intensity of europium(III), terbium(III) and samarium(III) tris-P-diketonates in toluene solutions and chemiluminescence intensity of europium(III) and samarium(III) tris-P-diketonates in the reaction with dioxetane. J Photochem Photobiol A Chemistry 2000 136 203-8. 

Fig. 6. Plot of association constants for Ln " " and [Ln(D02A)]" to DPA against lanthanide ionic radius, 0.2 M NaOAc, pH 7.5. The addition of D02A enhances dipicolinate binding affinity by an order of magnitude for most lanthanides investigated and by nearly two orders of magnitude for terbium (light gray).

We plan to take advantage of ligand-induced enhancement of dipicolinate binding affinity to improve current bacterial spore detection technologies in two ways. The first involves appending terbium(macrocycle) complexes to solid polymer substrates to improve microscopy-based endospore assays. In a second method, we will bind lanthanide complexes to silica to concentrate dipicolinate from very dilute samples on colmnns. 

The complex of A-(2-pyridinyl)-3-ketobutyramide with Tb + in methanol solution can emit the intrinsic fluorescence of Tb +. When EtsN and Zn + are added to the solution, the fluorescence (kex = 329 nm, ka = 546 nm) is significantly enhanced. This sensitive fluorescence enhancement system can be used for the determination of terbium ion ". ... 

Some lanthanide /3-diketonate complexes (11, M = Pr, Eu, Dy, R = n-Pr, R = f-Bu) have selectivity for further coordination with Cl ions, over F , Br , I , C104, SCN , OH, AcO , HCOs, N03 and SOa ", and are the active component of ion-selective electrodes (ISE) for CG. It was proposed to take advantage of the luminescence in the visible range associated with CH complexation, for the development of specific naked eye optodes (M = Eu) for this ion . A sensitive fiuorescence enhancement system for the determination of terbium was developed and studied. This method was applied to... 

When Nd or Yb complexes of a similar macrocycle are covalently linked to a palladium porphyrin complex, this sensitizes near-IR emission from the lanthanide, enhanced in the absence of oxygen and in the presence of a nucleic acid7 Another application of luminescence accompanies the terbium complex shown in (39) whose luminescence is enhanced by binding to zinc, and can therefore signal for that metal. " ... 

Details have appeared of a photovoltaic cell having a high conversion efficiency in which the output efficiency is enhanced by use of a phosphor film containing a terbium bipyridine complex, and of a photorechargeable battery incorporating a conducting polymer of polypyrrole deposited on carbon fibres coated with ferric chloride. The irradiated electrode is thought to possess semiconductor... 

The paper summarizes recently investigated properties of a structure microporous xerogel/mesoporous anodic alumina , doped with erbium, terbium and europium. An enhancement of green, red and infiared photoluminescence (PL) from the structure associated with intra-transitions of bivalent lanthanides in xerogels is discussed. 

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