TY - JOUR
T1 - Decay time distribution analysis of Yt-base in benzene-methanol mixtures
AU - Gryczynski, Ignacy
AU - Wiczk, Wieslaw
AU - Lakowicz, Joseph R.
AU - Johnson, Michael L.
N1 - Funding Information:
This work was supported by Grants GM 35154 and GM 39617 from the National Institutes of Health and Grants DMB 8804931 and 8502835 from the National Science Foundation. The authors wish to thank Professor Stefan Paszyc (Adam Michiewicz University, Poznan, Poland) for providing Y,-base. J.R.L. and W.W. acknowledge support from the University of Maryland Medical Biotechnology Center. This work was performed using facilities at the Center for Fluorescence Spectroscopy, University of Maryland.
PY - 1989/11
Y1 - 1989/11
N2 - Frequency-domain fluorometry was used to measure intensity decays of synthetic Yt-base in mixtures of benzene-methanol at 20 °C. Multiexponential analysis shows that the decay of Yt-base fluorescence in benzene and methanol can be well fitted to a single-exponential model with τ = 9.67 ns and 6.25 ns respectively. In mixtures of benzene-methanol the decays became heterogeneous, and the maximum of heterogeneity observed was in a mixture containing 6% methanol. Since we expected a distribution of Yt-base solvation states in the solvent mixtures, and because the decay times of Yt-base are sensitive to solvent, we analyzed the data in terms of decay time distributions. The goodness-of-fit for the unimodal distribution model which has two floating parameters was equivalent to that found using the double exponential model with three floating parameters. The Lorentzian distribution model appears to provide a slightly superior fit relative to the Gaussian distribution model. These results suggest that the intensity decays of solvent-sensitive fluorophores in mixed solvents are described by a distribution of decay times.
AB - Frequency-domain fluorometry was used to measure intensity decays of synthetic Yt-base in mixtures of benzene-methanol at 20 °C. Multiexponential analysis shows that the decay of Yt-base fluorescence in benzene and methanol can be well fitted to a single-exponential model with τ = 9.67 ns and 6.25 ns respectively. In mixtures of benzene-methanol the decays became heterogeneous, and the maximum of heterogeneity observed was in a mixture containing 6% methanol. Since we expected a distribution of Yt-base solvation states in the solvent mixtures, and because the decay times of Yt-base are sensitive to solvent, we analyzed the data in terms of decay time distributions. The goodness-of-fit for the unimodal distribution model which has two floating parameters was equivalent to that found using the double exponential model with three floating parameters. The Lorentzian distribution model appears to provide a slightly superior fit relative to the Gaussian distribution model. These results suggest that the intensity decays of solvent-sensitive fluorophores in mixed solvents are described by a distribution of decay times.
KW - Frequency-domain fluorometry
KW - Lorentzian distribution.
KW - fluorescence decay
KW - multiexponential analysis
UR - http://www.scopus.com/inward/record.url?scp=0024762824&partnerID=8YFLogxK
U2 - 10.1016/1011-1344(89)80002-8
DO - 10.1016/1011-1344(89)80002-8
M3 - Article
C2 - 2512379
AN - SCOPUS:0024762824
SN - 1011-1344
VL - 4
SP - 159
EP - 170
JO - Journal of Photochemistry and Photobiology, B: Biology
JF - Journal of Photochemistry and Photobiology, B: Biology
IS - 2
ER -