Hanna Instruments HI 84432 User Manual
Page 5
5
The Titratable Acidity determination is instantaneously displayed in selected measurement units
on the large dot matrix display. The instrument is ready for the next analysis immediately.
Other features:
• Log on demand up to 100 samples (50 for pH measurement; 50 for titration results)
• GLP feature, to view last calibration data for pH electrode and pump
MEASUREMENT SIGNIFICANCE
The HI 84432 measures the concentration of titratable hydrogen ions contained in the fruit juice
samples, by neutralization with a strong base solution to a fixed pH. This value includes all the
substances of an acidic nature in the fruit juice: free hydrogen ions, organic acids, acid salts and
cathions. Because the organic acid is the most acidic component of fruit juices that react with strong
bases solutions, the titratable acidity is usually expressed as g/L or g/100 mL of the predominant
acid contained:
•
Citric acid is present in many fruit species.
•
Tartaric acid is essentially found in grapes.
•
Malic acid is present in many fruit species, sometimes together with citric acid or tartaric
acid in unripe grapes.
The titratable acidity of fruit is an important parameter in determining fruit maturity.
The HI 84432 minititrator uses a method based on the Official Methods of Analysis of AOAC International.
The fruit juice is titrated with a sodium hydroxide solution until the end point at 8.2 pH is reached
(determined by potentiometric method).
Additionally the HI 84432 has a built-in pH meter for pH measurement (electrode and meter must
be calibrated).
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