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Fluorescence Lifetimes
kf ki Pulse of Excited light fluorophore w/10ns decay fluorophore w/2ns decay
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Fluorescence F Absorption Fluorescence Emission Higher Energy
400 500 600 700 Higher Energy Longer Wavelength Short Wavelength Excitation Long Wavelength Emission Absorption Fluorescence Emission INTENSITY 400 450 500 550 600 650 WAVELENGTH (nm)
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Fluorescence Emission is Sensitive to Solvent Conditions
More polar conditions generally yield a RED SHIFT in emission Less polar conditions usually result in a BLUE SHIFT Increasing Solvent Polarity INTENSITY 400 450 500 550 600 650 WAVELENGTH (nm) 400 500 600 700 Longer Wavelength Higher Energy
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Solvent Effects
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Solvent Relaxation
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Solvent Relaxation of ANS
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Quinine Sulfate in 0%, 25%, 50% and 75% EtOH
Intensity Change Wavelength Shift
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Lippert Equation
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Lifetime t0 = 1/G t = 1/(G + k) Quantum Yield Q = t0/ t Intensity Iem = Q·f(l)·Iex ·(l) ·C·Z
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Quantum Yield Measurements
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Inner Filter Effects
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Fluorescence Instrumentation
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