8
PRINCIPLE OF OPERATION
A neutralization titration is one where an acid and base react to form a neutral pH solution.
H
+
+OH¯
→
H
2
O
A potentiometric acid-base titration employs an indicator electrode (such as a pH sensor) to establish
the equivalence point of the titration.
The accepted methodology for Titratable Acidity in dairy products employs a neutralization titration.
Acids (such as lactic acid) in the milk products react with a base (the titrant sodium hydroxide) to
produce water. When manually performed, the exact sample volume, titrant volume and titrant
concentration must be known. Additionally, the endpoint determination can be subjective when a
visual indicator (phenolphthalein) is utilized in an opaque or colored sample. Calculations are then
required. The entire procedure can be quite time consuming.
Titratable Acidity in dairy products, as performed on the
HI 84429
minititrator, utilizes a simple
sample preparation, a high quality peristaltic dosing pump for titrant, potentiometric endpoint
detector and instantaneaous computations. To maintain the high precision of the titrator, a simple
pump calibration procedure is required. The calibration involves the analysis of a known volume of
a known solution (standard provided) and compensates for changes in pump dosing that may occur
due to many factors including tube stretching or aging. This procedure should be performed regularly.
