# The quantum efficiency of fluorescence ff can be written as where t is the observed lifetime of the.

The quantum efficiency of fluorescence ff can be written as

where t is the observed lifetime of the excited state in the

presence of a quenching agent and t0 is the natural lifetime in the absence of

a quencher. The fluorescence radiant power F is given by Equation 15-7. This

quantity is affected by collisional quenching because the lifetime t is

influenced by collisional quenching. Derive an equation to show that the F-t

ratio is independent of collisional quenching and directly related to

concentration. (From G. M. Hieftje and G. R. Haugen, Anal. Chim. Acta, 1981,

123, 255, DOI: 10.1016/S0003-2670(01)83178-0.)

101:

The following lifetimes were measured for the chloride

quenching of quinine sulfate given in Example 15-1. The fluorescence

intensities are given in the example.

(a) Plot fluorescence intensity versus [Cl^{–}].

(b) Plot the ratio of intensity to lifetime, F-t versus [Cl^{–}].

(c) Develop a normalization factor to correct the measured

fluorescence intensity to that of the solution without quencher.

(d) Plot on the same graph F versus [Cl^{–}] and F_{corr}

versus [Cl^{–}].