Atkins & de Paula:
Physical Chemistry for the Life Sciences
The equation for a Stern-Volmer plot for the determination of the kinetics of fluorescent decay and quenching is given by
Where Q is the quencher concentration (mmol L-1), If is the fluorescence intensity, Iabs is the intensity of absorption of the incident radiation, and kf and kq are the reaction rate constants.
To disentangle kq/kf the time constant of the decay can be measured in a pulse experiment. The rate law immediately after a brief flash of radiation has the soultion
Therefore, a plot of 
(s-1) against Q gives kf as the intercept and kq as the
slope of the best fit line. Note, can be obtained from the shape of the flourescence intensity
curve as a function of time.
To calculate kq, kf and half-life of fluorescent decay, enter data pairs
(Q, 
), and then click the Plot tab. To see the calculated values
click the Least-Squares Analysis tab. To pick off a value on the graph, move your cursor to the
desired location then click and hold.