Total Emission Time Resolved Decay: a Method for Measurement and Resolution of Broad-Band Emission
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ORIGINAL ARTICLE
Total Emission Time Resolved Decay: a Method for Measurement and Resolution of Broad-Band Emission Suraj Kumar Panigrahi 1
&
Ashok Kumar Mishra 1
Received: 11 April 2020 / Accepted: 26 June 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract This article reports a time-resolved fluorescence data acquisition technique termed as “Total Emission Time Resolved Decay” (TETRD). TETRD is recorded by using zero-order diffraction of emission grating in TCSPC instrument. TETRD decay curve has entire wavelength dependent decay information buried in it. Cut-off filters are used to avoid scattering contamination. Two existing approaches are used for analysing the interconnected TETRD data. (i) First, global analysis: for discretely decaying multiple components, TETRD dataset is analyzed using global analysis. The normalized pre-exponentials (αi) and relative amplitudes (fi) recovered from global analysis reflect the individual component emission more faithfully and resembles with steady-state spectral data as well. (ii) Second, stretched exponential fitting (StrEF): for continuous lifetime distribution systems, StrEF (I(t) = I0 exp[−(t/τ)1/h]) has been used to analyse TETRD data. The average lifetime (τ) of StrEF matches well with the average lifetime of multi-exponential fitting, the heterogeneity factor (h) of StrEF is an additional parameter, which informs about local heterogeneity in the system. It is shown that the lifetimes obtained with TETRD matches well with the lifetimes obtained using conventional time resolved emission spectra (TRES). TETRD holds advantage in rapid data acquisition and facilitates inclusion of another variable (like concentration, solvent composition, pH, excitation wavelength etc.) into experimental design. Further, with the use of an appropriate data analysis tool, the multi-component decay profiles can be resolved conveniently. Keywords Multi-fluorophoric systems . Multi-component fluorescence decay . Humic fluorescence decay . Total emission decay
Introduction Time-resolved fluorescence measurements are proven techniques that allow both identification and quantitative monitoring of specific fluorophores in the local environment. Time resolved emission spectra (TRES) has been widely used to understand the dynamics of multiple emissive systems such as: dynamics of proteins and membranes [1, 2], nano sciences [3] and photo physical studies [4–6]. Over the years, TRES data have been subjected to many refinements to get rational information out of it; consequently many analytical methods have been evolved. Knutson et al. have extracted decay associated spectra form TRES data [7]; decay associated spectra Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10895-020-02581-4) contains supplementary material, which is available to authorized users. * Ashok Kumar Mishra [email protected] 1
Indian Institute of Technology, Madras, Chennai 600036, India
signifies spectral contribution of individual fluorophore
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