Hanna Instruments HI 84432 User Manual
Instruction Manual
HI 84432
TITRATABLE ACIDITY
MINITITRATOR & pH METER
for Fruit Juices
www.hannainst.com
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Dear Customer,
Thank you for choosing a Hanna product. This manual will provide you with the necessary
information for the correct use of the instrument. Please read it carefully before using the meter.
If you need additional technical information, do not hesitate to e-mail us at tech@hannainst.com.
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TABLE OF CONTENTS
PRELIMINARY EXAMINATION................................................................................................. 4
GENERAL DESCRIPTION ........................................................................................................ 4
SPECIFICATIONS ................................................................................................................... 6
PRINCIPLE OF OPERATION .................................................................................................... 7
FUNCTIONAL AND PHYSICAL DESCRIPTION............................................................................. 8
TITRATOR STARTUP ........................................................................................................... 11
SETUP CONFIGURATION MENU .......................................................................................... 12
ELECTRODE PREPARATION .................................................................................................. 16
ELECTRODE CALIBRATION PROCEDURE................................................................................. 17
pH BUFFER TEMPERATURE DEPENDENCE............................................................................ 22
PUMP TUBE INSTALLATION................................................................................................. 23
PURGE .............................................................................................................................. 24
PUMP CALIBRATION PROCEDURE ........................................................................................ 26
TITRATION PROCEDURE ..................................................................................................... 29
pH MEASUREMENT ............................................................................................................ 34
TEMPERATURE CALIBRATION PROCEDURE (for technical personnel only) ............................... 38
TROUBLESHOOTING GUIDE ................................................................................................ 40
ELECTRODE CONDITIONING AND MAINTENANCE .................................................................. 41
ACCESSORIES .....................................................................................................................42
WARRANTY........................................................................................................................43
All rights are reserved. Reproduction in whole or in part is prohibited without the written consent
of the copyright owner, Hanna Instruments Inc., Woonsocket, Rhode Island, 02895, USA.
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PRELIMINARY EXAMINATION
Please examine this product carefully. Make sure that the instrument is not damaged. If any
damage occurred during shipment, please notify your Dealer.
Each HI 84432 minititrator is supplied complete with:
• HI 1131B pH electrode
• HI 7662-M Temperature probe
• HI 84432-50 Titrant solution (100 mL)
• HI 84432-55 Pump calibration solution (100 mL)
• HI 70004 pH 4.01 buffer solution (2 x 20 mL)
• HI 70007 pH 7.01 buffer solution (2 x 20 mL)
• HI 700082 pH 8.20 buffer solution (2 x 20 mL)
• Two 100 mL beakers
• Tube set with dispensing tip
• Stir bars (medium 2 pcs.)
• 12 Vdc power adapter
• Instruction manual
Note: Save all packing material until you are sure that the instrument works correctly. Any
defective item must be returned in its original packing.
GENERAL DESCRIPTION
The HI 84432 is an easy to use microprocessor-based automatic minititrator and pH meter designed
for the rapid and accurate analysis of Total Titratable Acidity in fruit juices. By eliminating subjective
factors including color indicators, errors in mathematical calculations or erratic titrant additions from
the measurement, the HI 84432 makes Total Titratable acidity analysis precisely. This will quickly
become a valuable acidity analysis tool of fruit juices.
The instrument benefits from Hanna’s many years of experience as a manufacturer of quality
analytical instruments. A clear and well-designed user interface makes the instrument intuitive and
simple to use. A dedicated HELP key aids in set-up, calibration, status and troubleshooting.
By simply pressing the START key, the HI 84432 automatically starts pump operation and titrates
the sample to the end point. The HI 84432 has a simple and accurate peristaltic pump to ensure the
best accuracy and repeatability. By performing pump calibration with the Hanna standard provided,
the instrument accuracy is ensured.
The instrument employs a powerful and effective built-in algorithm to analyze the pH response to
determine the exact pH endpoint, then uses this to make the necessary calculations.
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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.
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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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SPECIFICATIONS
Titrator Range Titratable acidity (low range): 15 mL sample
g/100 mL
g/100 mL
g/100 mL
Titratable acidity (high range): 2 mL sample
g/100 mL
g/100 mL
g/100 mL
Resolution 0.01%
Accuracy 5% of reading or ± 0.02
Titration method Acid-base titration
Principle End point titration: 8.20 pH
Pump debit 0.5 mL/min
Stirring speed 600 rpm
Log data Up to 50 samples
pH meter pH meter -2.0 to 16.0 pH / -2.00 to 16.00 pH
pH Resolution 0.1 pH / 0.01 pH
pH Accuracy ± 0.01 pH
pH Calibration 1, 2 or 3 calibration points;
3 available buffers (4.01; 7.01; 8.20)
Temperature manual or automatic from
compensation -20 to 120 °C (-4 to 248 °F)
Log data Up to 50 samples
Temperature Range -20.0 to 120.0 °C (-4.0 to 248.0 °F)
Resolution 0.1 °C
Accuracy ±0.4 °C without probe error
Electrode HI 1131B (included)
Temperature Probe HI 7662-M (included)
Environment 0 to 50 °C (32 to 122 °F); max 95% RH non-condensing
Power supply 12 Vdc power adapter
Dimensions 208 × 214 × 163 mm (8.2×8.4×6.4”) (with beaker)
Weight 2200 g (77 oz.)
as citric acid: 0.20 - 1.20% CA
as tartaric acid: 0.23 - 1.41% TA
as malic acid: 0.21 - 1.26% MA
as citric acid: 0.80 - 8.00% CA
as tartaric acid: 0.94 - 9.30% TA
as malic acid: 0.84 - 8.30% MA
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REQUIRED REAGENTS
Code Description Quantity/Test
HI 84432 - 50 Titrant 1 mL
HI 84432 - 55 Pump Calibration Solution 2 mL
PRINCIPLE OF OPERATION
Fruit juice acidity is determined by neutralization of all available hydrogen ions present in the
sample, with a strong base solution:
+
H
+HO- H2O
In an ideal solution, the end point of an acid titration corresponds stoichiometrically to the complete
neutralization of the acids present.
The HI 84432 minititrator is designed to determine the acidity of fruit juices by potentiometric
titration. The result of the titration are displayed in % (g/100 mL) of the predominant acid (citric,
malic or tartaric acid).
Using a pH electrode allows an end point at 8.2 pH to be automatically detected. End point
detection by potentiometric method is more objective than the end point detection using the
indicators.
For precise results the sample and titrant volume and the titrant concentration must be known.
It is important to titrate fresh samples of the fruit juice. For increased measurement precision keep
the fruit juices in capped vessels (avoid prolonged exposure to air). Also avoid refrigerating the juice
as significant portion of the tartaric acid (ex. grapes juice) will precipitate out and the results
obtained will be lower then expected results.
Titratable Acidity in fruit juices, as performed on the HI 84432 minititrator, utilizes a simple sample
preparation, a high quality peristaltic dosing pump for titrant, potentiometric endpoint detector and
instantaneous computations. To maintain the high precision of the titrator, a simple pump calibration
procedure is required. The pump 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 a minimum of
daily.
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FUNCTIONAL AND PHYSICAL DESCRIPTION
OVERHEAD VIEW
1. Titrant bottle
2. Graphic LCD
3. Keypad
4. Dedicated guide tube
for Temperature Probe
5. Electrode holder
6. Dedicated guide tube for titrant tip
7. Peristaltic pump tube
FRONT VIEW
REAR VIEW
8. Temperature probe
9. pH Electrode
10. Beaker
11. BNC electrode connector
12. Temperature probe socket
13. Power switch
14. Power adapter connector
15. Peristaltic pump
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KEYPAD FUNCTION AND INDICATORS
ESC - used to leave the current screen and to return either to the previous screen or to the
main screen. When pressed while modifying a parameter within the SETUP menu,
exits parameter without changing it.
/
- used to modify the parameters’ values, to scroll the information displayed while
viewing a help or to move between the options from the instrument’s SETUP
HELP - used to access/leave the instrument’s contextual help
MENU - used to enter SETUP, Recall or GLP selection menu, while instrument is in pH or
Titration main screen
STIR - used to start/stop the stirrer.
Note: The stirrer starts automatically during pump calibration and titration and cannot be
stopped by pressing STIR key.
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GUIDE TO INDICATORS
During the instrument’s operation information is displayed on the LCD.
Displayed icons:
Unstable reading.
Stirrer on.
1. Current time and instrument mode information (pH meter or Titrator)
2. Main reading information
3. Instrument status information
4. Functional key area
5. Indicates that the displayed value can be changed using ARROW keys
6. Temperature value (Manual or Automatic)
7. pH temperature compensation mode (Manual or Automatic)
8. Stirrer and reading status area
PERISTALTIC PUMP
Peristaltic pumps are self priming. Liquid never contacts the pump components. The titrant tubing
is pressed along the rotating rollers of the pump. The rollers compress the tubing, driving the
titrant to the dispensing tip.
Note: It may be necessary to compress the tubing against rollers with your finger to hasten the
filling of the tubing the first time.
Pump running.
Parameter can be changed.
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TITRATOR STARTUP
This is a general outline of the steps required to make a titration. The following topics are
expanded upon each section that follows.
• Place the instrument on a flat table. Do not place the instrument in direct sun light.
• Connect the power adapter to the instrument.
• Turn the instrument ON using the power switch from the rear panel of the instrument.
• Set up the instrument. See the “Setup Configuration Menu” section for details. Pay attention
to the Acidity Unit.
• Connect the pH sensor and temperature probe to the instrument.
• Calibrate the pH electrode. At least a single point calibration is necessary for titration.
• Place the peristaltic pump tube on the pump (inlet tube is connected with the reagent bottle,
outlet tube is connected with the dosing tip). See the “Pump Tube Replacement” section for
the procedure.
• Remove the reagent bottle cap and replace with the bottle cap with tubes. Place the reagent
bottle in the appropriate place on the titrator top.
• Purge the titrant. Verify titrant is leaving titrant tip.
• Calibrate the pump.
• Prepare the sample.
Note: Different volumes of juice are required for measurement accuracy. See SAMPLE PREPARATION
for details.
• Run a titration and log sample results.
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SETUP CONFIGURATION MENU
The titrator’s setup configuration menu may be accessed from the pH or titration screens by
pressing the MENU key, then Setup.
A list of setup parameters will be displayed with currently configured setting.
While in the setup menu it is possible to modify the instrument’s operation parameters. The
ARROW keys permit the user to scroll the setup parameters.
Press HELP to view the contextual help.
Press ESC to return to the main screen.
Concentration unit
Options: %CA; %TA; %MA.
Press the corresponding function key to change
the option.
Calibration timeout
Options: Disabled or 1 to 7 days.
This option is used to set the number of days
before the pH calibration expired warning message
is flagged.
Press Modify to access the calibration timeout
value modify parameter.
pH resolution
Use the ARROW keys in order to increase/
decrease the value.
Press Accept to confirm or ESC to return to the
setup menu without saving the new value.
Options: 0.1, 0.01.
Press the displayed function key in order to change
the pH resolution.
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Temperature unit
Backlight
Options: °C, °F.
Press the function key in order to change the
temperature unit.
Options: 0 to 8.
Press Modify to access the backlight level.
Contrast
Use the ARROW keys or
increase/decrease the displayed constrast.
Press Accept to confirm or ESC to return to the
setup menu.
Option: 0 to 20.
This option is used to set the display’s contrast.
Press Modify to change the display’s contrast.
Use the ARROW keys or / in order to
increase/decrease the value.
Press Accept to confirm the value or ESC to
return to the setup menu.
/ in order to
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Date / Time
Time format
This option is used to set the instrument’s date
and time.
Press Modify to change the date/time.
Press / to highlight the value to be
modified (year, month, day, hour, minute or
second). Use the ARROW keys to change the
value.
Press Accept to confirm the new value or ESC to
return to the setup.
Option: AM/PM or 24 hours.
Press the functional key to select the new value.
Date format
Press Modify to change the Date Format.
Use the ARROW keys to select the desired
format.
Press Accept to confirm the value or ESC to
return to the setup menu.
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