USING AN AUTOMATIC TITRATOR

Automatic titrators work to high analytical standards and are particularly useful when a large number of similar titrations are to be done.
They can carry out a variety of types of titration such as

Acid-Base Titration

Oxidation-Reduction Titration

Photometric Titration

Conductometric Titration

Each type of titration has its own dedicated burette.
A titration vessel containing automatic detection system commonly an ion specific combination electrode and titration parameters which are stored under discrete method numbers in the instrument.

Begin by
Choosing the relevant titrant, fitting the automatic burette and
keying in the appropriate method number for the titration.
Ensure that correct electrode is fitted to the titration.
Always wash the electrode with distilled water before use and between measurements.
Fit a beaker containing a pipetted aliquot of the acid sample and sufficient distilled water to ensure that the tip of the electrode is completely submerged.
Press the run button to begin the titration process
And then set the detailed titration parameters e.g. Identity of sample, sample weight or sample volume.
Press the run button again to activate the stirrer and carry out the titration.
The progress of the titration is shown on the LED display.
During the titration, the automatic burette delivers metered volumes of titrant.
These volume and the corresponding electrode readings are stored in the memory ready for access at the end of the titration.
When the titration is complete, the printer can plot out the results in a variety of formats.
As a full set of millivolt or PH data points with the corresponding titrant volumes, a table of result together with the graph or as here, simply a graph of PH versus titrant volume.
The end point corresponds to the mid-point of the steep section where the PH changes most rapidly.

Note that this machine plots the volume in milliliters which are equivalent to cubic centimeters.
Here, the machine had plotted the result of a strong acid–strong bas titration as millivolt versus volume.
Again, the end point is at the mid-point of the steepest section of the curve.
A plot of the first derivative of such millivolt or PH curves can also be produced.

In such plot, the end point is much more obvious as the point where the slope of the curve changes direction.
Such plots are particularly helpful when it is difficult to determine the mid-point of the steep section such as in the titration of a weak acid with a weak base or vice versa.
At the end of any titration, remove the sample beaker and rinse the stirrer, burette tip and electrode.

Note that electrodes must not be allowed to dry out. So immerse them in reference electrolyte when not in use.