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Introduction
effect on the fluorescence. As the quencher concentration increases the probability of
SOA quenching increases. In SOA quenching, the fluorescence intensity is reduced
by the quencher but the fluorescence decay is unaffected as the observed fluorescence
only comes from the uncomplexed fluorophores in the sample. The action of SOA
quenching can be described by:
I0
I = exp(VqN[Q]) (1.9)
where I0 is the incident light intensity, I is the fluorescence intensity and N is
Avogadro’s number[36, 38].
Comparison of dynamic and static quenching: The two mechanisms are com-
pared in Figure 1.11.
Figure 1.11: Comparison of dynamic and static quenching. Reproduced from [36]
For both dynamic and static quenching, the dependence of I0/I on [Q] is lin-
ear and the two mechanisms can not be distinguished by intensity measurements
alone. Lifetime measurements can be used to distinguish between dynamic and
static quenching. For static quenching the lifetime remains unchanged as only the
concentration of emitting fluorophores is reduced by formation of the complex and
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