摘要:

Phase-modulation fluorometry is the frequency-domain analogue of time-resolved fluorescence spectroscopy. During the past three years we witnessed the development of variable-frequency phase-modulation fluorometers with modulation frequencies from 1 to 220 MHz. These instruments provide impressive resolution of multi or non-exponential fluorescence decays. To introduce these instruments we describe their design and operational principles. To illustrate the obtainable resolution we present results for the resolution of two and three-component mixtures of fluorophores, the resolution of complex anisotropy decays from non-spherical molecules and the determination of time-resolved emission spectra in the presence of time-dependent spectral relaxation. At present, the resolution obtainable with the frequency-domain fluorometers appears to be at least equivalent to that obtained with pulsed mode-locked laser sources with single photon counting. These mode-locked sources can also be used for phase fluorometry, as described elsewhere in this volume by Gratton and co-workers.

ISSN:1073-9149    

DOI:10.1080/10739148508543578

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

We describe the construction and operation of a cross-correlation phase and modulation fluorometer which uses the harmonic content of a high repetition rate mode-locked laser as the excitation source.

ISSN:1073-9149    

DOI:10.1080/10739148508543579

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The use of phase-resolved fluorescence spectroscopy (PRFS) for the determination of fluorescence lifetimes using both phase delay and demodulation relationships is compared with determinations using direct measurements of phase delay and demodulation. In the PRFS approach, values for the phase delay and demodulation were found from cosinusoidal curves constructed from the time-independent phase-resolved intensity data, using both cosine fits and polynomial fits. Results for the phase and modulation fluorescence lifetimes of PRODAN, 9,10 diphenylanthracene and 1,2,5,6 dibenzanthracene found using the direct and the PRFS approaches were in excellent agreement. Precisions for the direct approach determinations were better than those for the PRFS approach for the longer-lived emissions and slightly worse for the shorter-lived emission of PRODAN. Results for heterogeneity analysis of mixtures of POPOP and 9,10 diphenylanthracene and of PRODAN are also compared for the two approaches.

ISSN:1073-9149    

DOI:10.1080/10739148508543580

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The basic methods of time-correlated single-photon counting are outlined briefly, and the advantages of rapid repetition-rate pulsed lasers as light sources in this experiment are outlined. Application of the method to time-resolved fluorescence anisotropy is described.

ISSN:1073-9149    

DOI:10.1080/10739148508543581

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

We review the interpretation of reconvolution analysis of single photon fluorescence decay data with regard to the time resolution achievable and sources of error encountered. Examples are presented for complex fluorescence decays in a wide range of applications including polymers, membranes, scintillators and solar collectors.

ISSN:1073-9149    

DOI:10.1080/10739148508543582

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This article reviews the advances that have been made in the technique of pulse fluorometry with time-correlated single photon counting detection brought about by the introduction of mode-locked synchronously pumped dye laser excitation. High repetition rates and small pulse width permit high data collection rates and excellent time-resolution. A modern pulse fluorometer which allows efficient measurement of fluorescence decay curves as well as automated measurement of time-resolved fluorescence spectra and of fluorescence anisotropy decays is described in detail.

ISSN:1073-9149    

DOI:10.1080/10739148508543583

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Sources for artefacts and distortions in data from a time correlated single photon counting spectrometer are described and illustrated. Methods are provided to avoid these instumental problems and to correct for the residual distortions.

ISSN:1073-9149    

DOI:10.1080/10739148508543584

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Methodologies for the simultaneous analysis of multiple total-intensity, anisotropy, and excited-state reactions are developed. Alternatives to the standard sums-of-exponentials fitting are proposed for both anisotropy and excited-state reaction data. Both simulation studies and real-data examples show these methods to be superior to single curve analysis.

ISSN:1073-9149    

DOI:10.1080/10739148508543585

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A general approach to calculate the individual spectra of species in excited state reactions is presented. Such spectra, which we call species associated spectra, SAS, are recovered from time-resolved emission data sampled at different wavelengths. SAS are presented in this paper for systems that also show ground state heterogeneity. Deconvolutions of single-photon-counting data have been carried out with the technique we call the global-reference method, i.e. global deconvolutions with quenched references, which also is discussed in the paper. Results are presented for global-reference deconvolutions of exponential decays and of fluorescence anisotropy described by anisotropic rotations of heterogeneously emitting systems. Some future projects are also discussed.

ISSN:1073-9149    

DOI:10.1080/10739148508543586

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

We describe the experimental techniques and methods of analysis used in our laboratory in the study of a wide range of chemical and biological systems. In addition to standard single exponential decay time measurements we discuss the resolution of multiexponential decays and the analysis of fluorescence anisotropy experiments.

ISSN:1073-9149    

DOI:10.1080/10739148508543587

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor