If the volume of a well mixed chamber (Vm) is much larger than the combined volumes of injector of connecting tubes and of detector, the concentration gradient generated by the flow system will decrease exponentially, as described by one tank (N=1) model.
This type of well defined concentration gradient has been used to dilute concentrated samples prior to detection (Gisin 1986), or to automate and speed up titrations.
In cFI titration, an acid sampler zone, injected into a carrier stream of a base containing an acid/base indicator will become gradually neutralized and therefore the width of the concentration gradient (Δt) will be proportional to the concentration of injected acid. Since the concentration gradient decreases exponentially with time, the width of the recorded peak will be proportional to log C of the injected acid. While fast and simple tyo perform, , the FI titrations are, due to this log/C dependence, less precise
than conventional titrations (Ruzicka & Hansen 1988).