Hanna Instruments HI 84432 User manual

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Instruction Manual
HI 84432
TITRATABLE ACIDITY
MINITITRATOR & pH METER
for Fruit Juices
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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 [email protected].
This instrument is in compliance with directives.

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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.
TABLE OF CONTENTS
PRELIMINARY EXAMINATION................................................................................................. 4
GENERAL DESCRIPTION ........................................................................................................ 4
SPECIFICATIONS ................................................................................................................... 6
PRINCIPLE OF OPERATION .................................................................................................... 7
FUNCTIONAL AND PHYSICAL DESCRIPTION............................................................................. 8
TITRATOR STARTUP ........................................................................................................... 10
SETUP CONFIGURATION MENU .......................................................................................... 11
ELECTRODE PREPARATION .................................................................................................. 15
ELECTRODE CALIBRATION PROCEDURE................................................................................. 16
pH BUFFER TEMPERATURE DEPENDENCE ............................................................................ 20
PUMP TUBE INSTALLATION ................................................................................................. 21
PURGE .............................................................................................................................. 21
PUMP CALIBRATION PROCEDURE ........................................................................................ 23
TITRATION PROCEDURE ..................................................................................................... 26
pH MEASUREMENT ............................................................................................................ 31
TEMPERATURE CALIBRATION PROCEDURE (for technical personnel only) ............................... 35
PC INTERFACE ................................................................................................................... 37
TROUBLESHOOTING GUIDE ................................................................................................ 40
ELECTRODE CONDITIONING & MAINTENANCE ...................................................................... 41
ACCESSORIES .....................................................................................................................42
WARRANTY ........................................................................................................................43

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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 7061M Cleaning solution (230 mL)
•HI 70300M Storage solution (230 mL)
•HI 7071 Filling solution (30 mL)
•HI 7004M pH 4.01 buffer solution (230 mL)
•HI 7007M pH 7.01 buffer solution (230 mL)
•HI 70082M pH 8.20 buffer solution (230 mL)
• HI 740142 One 1mL syringe
• HI 740037 Two 20 mL beakers
• Two 100 mL beakers • Tube set with dispensing tip
• Stir bars (small 2 pcs.) • 12 Vdc power adapter
• Instruction manual • One medium eye dropper
Note: Save all packing material until you are sure that the instrument works correctly. Any
defective item must be returned in its original packing.
PRELIMINARY EXAMINATION
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 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 assured.
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.
GENERAL DESCRIPTION

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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
• PC interface via USB connection
MEASUREMENT SIGNIFICANCE
Titratable acidity of fruit juices measures the concentration of titratable hydrogen ions contained in
the fruit juices samples, by neutralization with strong base solution at 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 the fruit juices that react
with strong bases solutions, the titratable acidity is usually expressed as g/L or g/100mL of the
predominant acid contained:
•Citric acid is present in many fruits 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.
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).
Additionaly the HI 84432 has a built-in pH meter for pH measurement (electrode and meter must
be calibrated).
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REQUIRED REAGENTS
Code Description Quantity/Test
HI 84432 - 50 Titrant 1 mL
HI 84432 - 55 Pump Calibration Solution 2 mL
SPECIFICATIONS
Titrator Range Titratable acidity:
g/100 mL as citric acid : 0.20 - 8.00% CA
g/100 mL as tartric acid : 0.23 - 9.30% TA
g/100 mL as malic acid : 0.21 - 8.30% MA
Resolution Titratable acidity:
0.01%
Accuracy 5% of reading ± 0.05
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.)

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PRINCIPLE OF OPERATION
Fruit juice acidity is determined by neutralization of the 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.
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.
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/100mL) of the predominant acid (citric,
malic or tartaric acid).
For precise results is important to know the sample volume and the titrant volume and concentration.
It is important to titrate fresh samples of the fruit juice. For increased measurement precision keep
the fruit juices in caped 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
instantaneaous 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 regularly.

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OVERHEAD VIEWOVERHEAD VIEW
OVERHEAD VIEWOVERHEAD VIEW
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 VIEWFRONT VIEW
FRONT VIEWFRONT VIEW
FRONT VIEW
REAR VIEWREAR VIEW
REAR VIEWREAR VIEW
REAR VIEW
8. Temperature probe
9. pH Electrode
10. Beaker
11. BNC electrode connector
12. Temperature probe socket
13. USB connector
14. Power switch
15. Power adapter connector
16. Peristaltic pump
FUNCTIONAL AND PHYSICAL DESCRIPTION

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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 stirer starts automatically during pump calibration and titration and cannot be
stopped by pressing STIR key.
1. Current time and instrument mode information (pH meter or Titrator)
2. pH electrode condition information
3. Main reading information
4. Instrument status information
GUIDE TO INDICATORS
During the instrument’s operation information is displayed on the LCD.
Displayed icons:
Unstable reading.
Stirrer on.
Pump running.
Parameter can be changed.
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5
2
3
4
9
6
8
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KEYPAD FUNCTION AND INDICATORS

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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.
TITRATOR STARTUP
This is a general outline of the steps required to make a titration. The following sections expand
upon each section.
• 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.
• Calibrate the pump.
• Prepare the sample.
• Run a titration and log sample results.
5. Functional key area
6. Indicates that the displayed value can be changed using ARROW keys
7. Temperature value (Manual or Automatic)
8. pH temperature compensation mode (Manual or Automatic)
9. Stirrer and reading status area