Hanna Instruments HI 84431 User manual

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Instruction Manual
HI 84431
TOTAL ALKALINITY
MINITITRATOR & pH METER
for Water Analysis
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 [email protected].

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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 ................................................................................................................... 7
PRINCIPLE OF OPERATION .................................................................................................... 8
FUNCTIONAL AND PHYSICAL DESCRIPTION ............................................................................. 9
TITRATOR STARTUP ........................................................................................................... 12
SETUP CONFIGURATION MENU .......................................................................................... 13
ELECTRODE PREPARATION .................................................................................................. 18
ELECTRODE CALIBRATION PROCEDURE................................................................................. 19
pH BUFFER TEMPERATURE DEPENDENCE ............................................................................ 23
PUMP TUBE INSTALLATION ................................................................................................. 24
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 & 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 84431 minititrator is supplied complete with:
•HI 1131B pH electrode
•HI 7662-M Temperature probe
•HI 84431-50 Titrant low range (100 mL)
•HI 84431-51 Titrant high range (100 mL)
•HI 84431-55 Pump calibration solution (100 mL)
•HI 70004 pH 4.01 buffer solution (2 x 20 mL)
•HI 700083 pH 8.30 buffer solution (2 x 20 mL)
•HI 70010 pH 10.01 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.
PRELIMINARY EXAMINATION
The HI 84431 is an easy to use microprocessor-based automatic minititrator and pH meter designed
for the rapid and accurate analysis of Total Titratable alkalinity in water. By eliminating subjective
factors including color indicators, errors in mathematical calculations or erratic titrant additions from
the measurement, the HI 84431 makes Total Titratable alkalinity analysis precisely. This will
quickly become a valuable alkalinity analysis tool of waters and wastewaters.
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.
GENERAL DESCRIPTION

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By simply pressing START key, the HI 84431 automatically starts pump operation and titrates the
sample to the end point. The HI 84431 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. The Titratable
Alkalinity 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
Water alkalinity is expression of a waters acid-neutralizing capacity and it is determined by
titration with standard acid solutions.
Alkalinity is an important parameter for control and treatment of potable and wastewaters, because
it indicates the water buffering capacity (ability to resist at pH change, primarily because of
bicarbonate/ carbonate content). A low water alkalinity signifies that the water is susceptible to pH
change and high alkalinity indicates that water is able to resist a major change of pH. Alkalinity can
be used to estimate water hardness or to determine water corrosive capacity.
Alkalinity of surface water, quantified by mg/L as CaCO3 or meq/L, may be caused by carbonate,
bicarbonate, hydroxide, phosphates, borates, silicates or organic acids salts.
Conventionally, the water alkalinity is approximated as sum of components. Three types of alkalinities
exist together to form total alkalinity:
TA = OH¯+ CO3
2¯+ HCO3 ¯
OH¯– hydroxide alkalinity
CO3
2¯– carbonate alkalinity
HCO3
¯– bicarbonate alkalinity
TA – total alkalinity
Different tests can be performed to determine the quantity of different alkalinities present. A
titration to pH 8.3 is considered Strong Alkalinity (SA) and to pH 4.5 Total Alkalinity (TA).

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The results of a titration provide a means to classify the principle forms of alkalinity.
Relationship of titrant volumes for alkalinity calculations:
According to the Standard Methods of Waters and Wastewaters Analysis, there are two options to
determine water alkalinity:
1) Strong alkalinity determination by titration of the water sample with strong acid solution
to 8.3 pH (known as phenolphtalein alkalinity).
2) Total alkalinity determination by titration of the water sample with strong acid solution
to 4.5 pH (known as bromcresol green alkalinity).
Potentiometric end point detection using a pH electrode is more objective than using visual end
point determinations with color changing indicators. The HI 84431 minititrator is a potentiometric
titrator. The instrument also can be used as a pH meter. The volume of titrant dispensed necessary
to reach the end point is then used to calculate the water alkalinity expressed in mg/L as CaCO3
meq/L as CaCO3.
Interferences:
•dissolved gases, lost or gained during samples storage or transport can modify the
alkalinity of the samples;
•presence in the samples of the: precipitates, solid suspensions, oils, soaps can coat a pH
electrode;
To eliminate or diminish the interference effects, it is recommended:
•to protect the samples against the atmospheric action (store in an airtight vessel);
•to avoid vigorous shaking or mixing: stir gently;
•maintenance of the pH electrode (see section Electrode Conditioning and Maintenance)
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SPECIFICATIONS
Titrator Range Titratable alkalinity (low range)
mg/L : 15.0 - 500.0 mg/L as CaCO3
meq/L : 0.3 - 10.0 meq/L as CaCO3
Titratable alkalinity (high range)
mg/L : 400 - 4000 mg/L as CaCO3
meq/L : 8 - 80 meq/L as CaCO3
Resolution Titratable alkalinity (low range):
0.1 mg/L
0.1 meq/L
Titratable alkalinity (high range):
1mg/L
1meq/L
Accuracy 5% of reading
Titration method Acid-base titration (total alkalinity / strong alkalinity)
Principle End point titration: 4.50 pH / 8.30 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; 8.30; 10.01)
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
Water alkalinity determination is performed by titration with acid reagent to pH end point.
Alkalinity is expressed as:
• Strong alkalinity (phenolphtalein alkalinity) determination by titration at 8.3 pH (in this
reaction hydroxide ions are converted to water and carbonate ions to bicarbonate ions):
2HO¯+ H2SO4→2H2O + SO4
2¯
2CO3
2¯+ H2SO4→2HCO3+ SO4 2¯
Since bicarbonate ions can be converted to carbonic acid with additional sulfuric acid, the
phenolphtalein alkalinity measure total hydroxide ions and one half of the bicarbonate
ions contribution.
• Total alkalinity determination by titration at 4.5 pH (completly convert of the bicarbonate ions):
2HCO3
¯+ H2SO4→2H2CO3+ SO4 2¯
It is important that the samples are protected against atmospheric factors (store them in sealed
bottles that are completely filled) and avoid vigorous shaking, mixing and long exposure to air.
The HI 84431 minititrator is designed to determine the alkalinity of waters by potentiometric
titration in a low range (10-500mg/mL as CaCO3) and in a high range (400-4000mg/mL as CaCO3).
Selection of the alkalinity range is limited by the pH sample: if the measured pH is greater than 8.3
both total and strong alkalinity can be determined. If the sample pH is lower than 8.3 only total
alkalinity can be determined.
The HI 84331 utilizes two different titration solutions to cover the entire measurement range. If the
range is changed, the titrant must be changed and the peristaltic pump must be primed and
recalibrated.
HI 84431-55 is used for pump calibration; the volume used will vary for the selected range.
Titratable Alkalinity in waters, as performed on the HI 84431 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.
REQUIRED REAGENTS
Code Description Quantity/Test
HI 84431 - 50 Titrant (Low Range) 1 mL
HI 84431 - 51 Titrant (High Range) 1 mL
HI 84431 - 55 Pump Calibration Solution 2 mL for low range
20 mL for high range

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FUNCTIONAL AND PHYSICAL DESCRIPTION
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. Power switch
14. Power adapter connector
15. Peristaltic pump

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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.
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.
1. Current time and instrument mode information (pH meter or Titrator)
2. pH electrode condition information
3. Main reading information
4. Instrument status information
5. Functional key area
6. Indicates that the displayed value can be changed using ARROW keys
7. Temperature value (°C, °F)
8. pH temperature compensation mode (Manual or Automatic)
9. Stirrer and reading status area
GUIDE TO INDICATORS
During the instrument’s operation information is displayed on the LCD.
Displayed icons:
1
5
2
3
4
9
6
8
7
Unstable reading.
Stirrer on.
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 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.
• 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 the bottle cap with the tubes. Place the reagent
bottle in the appropriate place on the titrator top (pay attention to the titration range).
• Purge the titrant.
• Calibrate the pump.
• Prepare the sample.
• Run a titration and log sample results.

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From your knowledge of expected concentrations, use the table below to determine which
settings and solutions are appropriate:
Use Total LR or Strong LR for waters alkalinity in the 10 - 500 mg/L range.
Use Total HR or Strong HR for waters alkalinity in the 400 - 4000 mg/L range.
Use the appropriate titrant for each range.
Also, the pump must be recalibrated when the measurement range is changed (see table above).
Alkalinity type
SETUP CONFIGURATION MENU
Options: mg/L, meq/L.
Press the corresponding function key to change the
option.
Concentration unit
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.
Options:Total LR (total alkalinity low range)
Total HR (total alkalinity high range)
Strong LR (strong alkalinity low range)
Strong HR (strong alkalinity high range)
Press the corresponding function key to change the
option.
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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.
pH resolution
Options: 0.1, 0.01.
Press the displayed function key in order to change
the pH resolution.
Options: °C, °F.
Press the function key in order to change the
temperature unit.
Temperature unit
Options: 0 to 8.
Press Modify to access the backlight level.
Backlight
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.

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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.
This option is used to set the instrument’s date
and time.
Press Modify to change the date/time.
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.
Option: 0to 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 displayed constrast.
Press Accept to confirm or ESC to return to the
setup menu.
Contrast
Date / Time

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Press the corresponding function key to change the
language.
If the new selected language cannot be loaded,
the previously selected language will be reloaded.
Language
Use the ARROW keys to select the desired format.
Press Accept to confirm the value or ESC to return
to the setup menu.
Date format
Press Modify to change the Date Format.
This option is used to enable/disable tutorial mode.
If enabled this option will provide the user short
guides on the screen.
Press the function key to select this option.
Tutorial
Option: AM/PM or 24 hours.
Press the functional key to select the new value.
Time format
If no language can be loaded at startup the instrument will work in the “safe mode”. In “safe
mode” all the messages are displayed in English and tutorial and help information are not
available
.

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Press Select to view the firmware version, language
version, mV factory calibration date and time and
temperature factory calibration date and time.
Press ESC to return to the Setup mode.
Meter information
Press the function key to select the new option.
When enabled, a short beep is heard every time a
key is pressed or when the calibration can be
confirmed.
A long beep alert sounds when the pressed key is
not active or a wrong condition is detected while
in calibration.
Beep On

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ELECTRODE PREPARATION
PREPARATION PROCEDURE
Remove the electrode protective cap.
DO NOT BE ALARMED IF ANY SALT DEPOSITS ARE PRESENT. This is normal with electrodes and
they will disappear when rinsed with distilled water.
During transport tiny bubbles of air may have formed inside the glass bulb. The electrode cannot
function properly under these conditions. These bubbles can be removed by "shaking down" the
electrode as you would do with a glass thermometer.
If the bulb is dry, soak the electrode in HI 70300 Storage Solution for at least one hour.

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ELECTRODE CALIBRATION PROCEDURE
It is recommended to calibrate the instrument frequently, especially if high accuracy is required.
The pH electrode should be recalibrated:
a) Whenever the pH electrode is replaced
b) At least once a week
c) After testing aggressive chemicals and after electrode is cleaned
d) When high accuracy is required
e) If the pH calibration expired warning is displayed during measurement. Every time
you calibrate the instrument clean the electrode (see the “pH Cleaning Procedure” section) and
use fresh buffers.
PROCEDURE
A single, two or three-points calibration can be performed, using the three predefined buffers
4.01, 8.30 and 10.01 pH. For a single point calibration any of the three buffers may be used,
but using 8.30 pH is recommended.
Note: The HI 84431 will not accept other pH buffers for calibration.
• Pour small quantities of selected buffer solutions into clean beakers. For accurate calibration use two
beakers for each buffer solution, the first one for rinsing the electrode and the second one for calibration.
• Put a magnetic stir bar in each beaker with the calibration buffer solution.
• Remove the protective cap and rinse the electrodes with some of the buffer solution to be
used for the first calibration point. Open fill hole on electrode.
• Put the first beaker with calibration buffer in the beaker holder.
• Place the electrode holder on the top of the beaker and secure it by turning clockwise.
• Immerse the pH electrode and the temperature probe approximately 2 cm (0.8”) into the
buffer paying attention not to touch the stir bar.
To select Electrode calibration screen follow the next steps:
• From pH meter screen press CAL function key then Electrode.
• From Titrator screen press CAL function key then Electrode.
• The electrode calibration screen will be displayed.
Point 1 calibration
• The 8.30 buffer will be selected by default. If necessary press the ARROW keys in order to
select a different buffer value.

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• The (unstable measurement) symbol will be shown on the display until the reading becomes stable.
• When the reading is stable and close to the selected buffer, the (unstable measurement)
symbol will disappear and the Confirm key will become active.
• Press Confirm to confirm the calibration.
• Press ESC to exit calibration.
Notes: • To clear a previous calibration and to return to the default value, press Clear at any
time after entering calibration mode. The “Calibration cleared” message will be
shown for a few seconds on the display. If Clear is invoked during the first calibration
point the instrument returns to the measurement mode.
• The Clear key is displayed only if a previous calibration exists.
Point 2 calibration
• The calibrated value will be shown on the display and the second expected buffer value will
be displayed.
• Remove the electrode holder with electrodes from the top of the beaker.
• Place the second buffer into beaker and place in beaker holder. Rinse the electrodes in a
beaker containing the second buffer rinsing solution.
• Place the electrode holder (with electrodes) on the top of the beaker, lock cap by turning.
• If necessary press the ARROW keys in order to select a different buffer value.
• The (unstable measurement) symbol will be shown on the display until the reading
becomes stable.
• When the reading is stable and close to the selected buffer, the (unstable measurement)
symbol will disappear and the Confirm key will become active.
• Press Confirm to confirm the calibration.
• The calibrated value will be shown on the display and the third expected buffer value will be
automatically selected.