Automated discontinuous titration

This wording may be considered as duplication, because one can hardly think of continuous titration without automation however, the intention is simply to stress its character as an alternative to automated discontinuous titrations. The principle of continuous titration can be illustrated best by Fig. 5.151 it applies to a steady stream of sample (C). Now, let us assume at first that the analyte concentration is on specification, i.e., it agrees with the analyte concentration of the standard (B). If, when one mixes the titrant (A) with the sample stream (C), the mass flow (equiv./s) of titrant precisely matches the mass flow of analyte, then the resulting mixture is on set-point. However, when the analyte concentration fluctuates, the fluctuations are registered by the sensor it is clear that the continuous measurement by mixing A and C is only occasionally interrupted by alternatively mixing A and B in order to check the titrant for its constancy. 

Automated titrations can be divided into discontinuous and continuous, the former representing a discrete sample analysis, as a batch titration is the usual laboratory technique and the latter a flow technique, which is used less frequently in the laboratory, e.g., in kinetic studies, but is of greater importance in plant and environment control. 

D.P. Arnold, M.R Russell, J.D. Petty, D.R. Sweatman, Automated titrations using a discontinuous programmed flow analyzer, Anal. Chem. 67 (1989) 2109. 

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