Hanna Instruments HI 84432 - Manual (Page 29)

29
Notes: • Check the pH of distilled water. If necessary,
adjust the pH to 8.2 by adding 1-2 drops of
titrant solution.
• Fruit juices samples must be stored in capped
bottles. Avoid disturbing any sediment in the
sample.
• Place the stir bar into the beaker and then place the
beaker in the appropriate place on the instrument top.
• Rinse off pH electrode and temperature probe with deionized
water into a waste container. Blot dry. Do not rub.
• Place the electrode holder with electrodes on the top of
the beaker and secure it by turning clockwise.
• Verify the pH and the temperature probes do not to touch
the stir bar. Use O-Rings provided to secure the pH
electrode in holder if necessary.
• Verify the dosing tip in the appropriate holder place and
immersed into the sample.
• From the titrator main screen press Titration. To enter
titrator main screen from pH meter mode press Titrator
and then Titration.
• Press Range to switch between low range (LR) and high range (HR).
• Verify the correct sample size is configured on instrument by seeing volume set displayed in
upper right corner.
TITRATION PROCEDURE
Verify: The instrument has been calibrated (pH and pump) before performing a lot of titrations.
An electrode calibration in at least one point (8.20 pH buffer) is recommended.
In order to increase the result accuracy, the measuring range was divided in two ranges:
Low range (LR): 0.20 to 1.20% CA
High range (HR): 0.80 to 8.00% CA
Depending on the expected sample concentration, different sample volume must be used for each
range, as followings:
• Sample preparation: Accurately measure volume of juice required to a clean dry beaker.
For Low range
0.20 to 1.20% CA use 15.00 mL
For High range 0.80 to 8.00% CA use 2.00 mL
Fill the beaker to the 50 mL volume mark with deionized water.