Hanna Instruments HI 901 - Manual (Page 56)

5-16
METHODS
This is rigorously exact only for symmetric S-shaped titration curves. For non-symmetric curves,
the effect of this theoretical error can be minimized by smaller doses (more measurement
points) around the equivalence point.
1st Derivative:
When first derivative is used to recognize the equivalence point, the point where the first
derivative reaches the maximum value corresponds to the titration curve inflection point (EQP).
The detection algorithm searches for the maximum value of the first derivative. Also, the first
derivative must be greater than the threshold value at the maximum point (see Recognition
Options on page 5-17).