| Frequency-domain measurement of luminescent lanthanide chelates. | |
| | |
MedLine Citation:
|
PMID: 20617797 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
The sinusoidal modulation of excitation intensity and phase-sensitive detection of emission is ideally suitable for the accurate determination of the lifetime and intensity of lanthanide luminescence. In this work we elaborate on the general mathematical and instrumental techniques of the frequency-domain (FD) measurements in the low-frequency domain below 100 kHz. A modular FD luminometer is constructed by using a UV-LED as the excitation source, proper light filters in the excitation and emission paths, a photomultiplier with a fast preamplifier, and a conventional dual-phase lock-in amplifier. Starting from the set of linear differential equations governing the excited-state processes of the lanthanide chelates, an equation linking the luminescence intensity to the general form of the excitation modulation was derived. Application to the sinusoidal modulation in the Euler's exponential form gives the expression for the in-phase and out-of-phase signals of a dual-phase lock-in amplifier. It is shown that by using a relatively large number of logarithmically equidistant modulation frequencies it is possible to use the Kramers-Kronig relation for checking the compatibility of the out-of-phase and in-phase signals. As an example, the emission from two different europium(III) chelates were measured by using 200 modulation frequencies between 10 Hz and 100 kHz. In addition to the conventional transition between (5)D(0) and (7)F(2) levels emitting at 615 nm, also the emission from the transition between (5)D(1) and (7)F(1) levels at ca. 540 nm was measured. The latter emission was also measured at different temperatures, yielding the energy difference between the (5)D(1) and (5)D(0) levels. The relatively large number of modulation frequencies allows also an accurate determination of lifetimes and corresponding amplitudes by using an appropriate nonlinear regression method. Comparison of the time-domain and frequency-domain methods shows that the weighting of data is different and both methods have application areas of their own. |
| | |
Authors:
|
Iko Hyppänen; Tero Soukka; Jouko Kankare |
Related Documents
:
|
18493287 - Two-dimensional grating light modulator for projection display. 20114077 - Functional and structural aspects of tinnitus-related enhancement and suppression of au... 3772827 - Gating of sensory information: joint computations of phase and amplitude data in the mi... 20563057 - Recording holograms with diagonal coding on binary spatial light modulators for pattern... 19380287 - Proinflammatory and prothrombotic effects on human vascular endothelial cells of immune... 3596987 - Nomarski evaluation of rod outer segment renewal in a hereditary retinal degeneration. ... |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: The journal of physical chemistry. A Volume: 114 ISSN: 1520-5215 ISO Abbreviation: J Phys Chem A Publication Date: 2010 Aug |
Date Detail:
|
Created Date: 2010-07-29 Completed Date: 2010-11-10 Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 9890903 Medline TA: J Phys Chem A Country: United States |
Other Details:
|
Languages: eng Pagination: 7856-67 Citation Subset: IM |
Affiliation:
|
Laboratory of Materials Chemistry and Chemical Analysis, Department of Chemistry, University of Turku, Vatselankatu 2, FI-20014 Turku, Finland. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Algorithms Chelating Agents / chemistry* Lanthanoid Series Elements / chemistry* Luminescence Models, Chemical* |
| Chemical | |
Reg. No./Substance:
|
0/Chelating Agents; 0/Lanthanoid Series Elements |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Erratum: The Unusual Solid-State Structure of Mercury Oxide: Relativistic Density Functional Calcula...
Next Document: Diquat derivatives: highly active, two-dimensional nonlinear optical chromophores with potential red...