Comparing organized media types using fluorescence probe characterization methods

Neal, Sharon L.; Villegas, Michele M.

doi:10.1016/0003-2670(94)00592-a

Cited by 12 publications

(2 citation statements)

References 45 publications

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“…e ., low monomer concentration) than those used to produce excimer formation. Second, the statistic was calculated under the assumption that the monomer decay rate is constant across the micelle microdomains, an assumption which other studies refute. − …”

Section: Introductionmentioning

confidence: 99%

“…Second, the statistic was calculated under the assumption that the monomer decay rate is constant across the micelle microdomains, an assumption which other studies refute. [17][18][19] Another model-independent analysis is described by Berberan-Santos et al 20 The sum of the system of kinetic equations is a first-order differential equation whose solution is a convolution of the intrinsic decays of all the species participating in a given kinetic mechanism. They estimate the decay constants by fitting experimental data to a convolution of exponential decays in which the decay constants are fitting parameters.…”

Section: Introductionmentioning

confidence: 99%

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Model-Independent Estimation of the Photokinetic Transfer Matrix from Matrix-Formatted Frequency-Domain Fluorescence

Neal

1997

J. Phys. Chem. A

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In this paper, the mathematical relationships between matrix-formatted frequency-domain fluorescence decay data and the photokinetic transfer matrix are derived. These relationships reveal that procedures for analyzing the fluorescence spectra and photokinetic mechanism of excited state reactions without model assumptions can be developed when the fluorescence decay is described by first-order differential equations with constant coefficients and when the spectral emission profiles of the decaying fluorophores are distinct. The linear structure of wavelength-dependent frequency-domain decay data permits the simultaneous estimation of the emission spectra, relative initial concentrations, and the photokinetic transfer matrix describing the decay and interaction of multiple fluorophores. Data matrices acquired using a single sample are amenable to this approach, eliminating the necessity to measure probe lifetimes separately at low fluorophore concentration. Most importantly, this method does not require that the analyst choose a kinetic model describing fluorophore emission. Instead, the kinetic mechanism is revealed in the structure of the transfer matrix. Statistical methods can be used to estimate the number of emitting components contributing to a data matrix, so that every aspect of the analysis can be pursued without a priori assumptions. Other analytical tools, including a procedure for matrix partitioning to estimate the spectra of sample fluorophores when the spectra are unknown and graphical tools for evaluating prospective spectra and decays, also are described.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Model-Independent Estimation of the Photokinetic Transfer Matrix from Matrix-Formatted Frequency-Domain Fluorescence

Neal

1997

J. Phys. Chem. A

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Fluorescence in Organized Assemblies

Hinze¹

2000

Encyclopedia of Analytical Chemistry

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This article provides an overview of the general properties of organized assembly (ordered media) systems such as aqueous surfactant and bile salt micelles, lipid and surfactant vesicles (liposomes) and cyclodextrins (CDs) and summarizes their utilization to enhance the performance of analytical fluorescence measurements. In many instances, organic molecules and metal complex species, when included within a CD cavity or solubilized and bound to surfactant aggregates, exhibit enhanced fluorescence. This gives rise to improved detectability of such analytes. The altered microenvironment within the organized medium is capable of impeding the interfering action of other species (inorganic or organic) present in the sample matrix. This often can improve the selectivity of the analytical method. These benefits of improved sensitivity and selectivity arise from the compartmentalization, isolation and shielding of the excited singlet state of the guest analyte from quenching and nonradiative decay processes as well as prevent side reactions that otherwise can occur in bulk solution (or sample matrix). In addition, organic solvents or time‐consuming extraction steps can be avoided owing to the increased solubility of the nonpolar organic or inorganic reagents and/or analyte molecules in water in the presence of the organized medium; allowing for the use of an aqueous medium to perform the procedure. The possibility of conducting reactions and forming fluorescent organic or metal chelates in micellar (or other organized) media that are not observed in a bulk homogeneous solvent system serves to expand the scope of chemistries that one can consider using to design/develop new, unique and improved fluorescent assays. Numerous representative examples of fluorescent methods for determination of both organic and inorganic analytes are provided which serve to illustrate the advantages and benefits accrued from the use of the micelles, vesicles, liposomes or CDs in such procedures. Some experimental considerations and cautions to keep in mind when utilizing organized media are also delineated. An extensive reference section is provided so that the interested reader can easily refer to such for more detailed information on these systems and topics.

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Fluorescence in Organized Assemblies

Memon¹,

Balouch²,

Hinze³

2008

Encyclopedia of Analytical Chemistry

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This article provides an overview of the general properties of organized assembly (ordered media) systems, such as aqueous surfactant and bile salt micelles, lipid (liposomes) and surfactant vesicles, and cyclodextrins (CDs), and summarizes their utilization to enhance the performance of analytical fluorescence measurements. In many instances, organic molecules and metal complex species when included within a CD cavity or solubilized and bound to surfactant aggregates exhibit enhanced fluorescence, improving detectability of such analytes. The altered microenvironment within the organized medium can impede the interfering action of other species (inorganic or organic) present in the sample matrix, which often improves the selectivity of the analytical method. These benefits of improved sensitivity and selectivity arise from the compartmentalization, isolation, and shielding of the excited singlet state of the guest analyte from quenching and nonradiative decay processes, as well as preventing side reactions that otherwise can occur in bulk solution (or sample matrix). Organic solvents or time‐consuming extraction steps can also be avoided, owing to the increased solubility of nonpolar organic or inorganic reagents and/or analyte molecules in water in the presence of the organized medium, allowing the use of an aqueous medium to perform the procedure. The possibility of conducting reactions and forming fluorescent organic or metal chelates in micellar (or other organized) media that are not observed in a bulk homogeneous solvent system serves to expand the scope of possible chemistries for design/development of new, unique, and improved fluorescent assays. Examples of fluorescent methods for determination of both organic and inorganic analytes are provided, which serve to illustrate the advantages and benefits accrued from the use of the micelles, vesicles, liposomes, or CDs in such procedures, along with experimental considerations and cautions in utilizing organized media.

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Comparing organized media types using fluorescence probe characterization methods

Cited by 12 publications

References 45 publications

Model-Independent Estimation of the Photokinetic Transfer Matrix from Matrix-Formatted Frequency-Domain Fluorescence

Model-Independent Estimation of the Photokinetic Transfer Matrix from Matrix-Formatted Frequency-Domain Fluorescence

Fluorescence in Organized Assemblies

Fluorescence in Organized Assemblies

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