Hanna Instruments HI96750C User manual

INSTRUCTION MANUAL
HI96750C
Potassium Low Range & Medium
Range ISM

Thank you for choosing a Hanna Instruments product.
Please read this instruction manual carefully before using the instrument.
This manual will provide you with the necessary information for correct use of
the instrument, as well as a precise idea of its versatility.
If you need additional technical information, do not hesitate to e‑mail us at
[email protected] or view our worldwide contact list at www.hannainst.com.
Dear
Customer,
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 ............................................................................................
GENERAL DESCRIPTION ....................................................................................................
ABBREVIATIONS ..............................................................................................................
SPECIFICATIONS ..............................................................................................................
PRECISION AND ACCURACY ..............................................................................................
PRINCIPLE OF OPERATION ...............................................................................................
FUNCTIONAL DESCRIPTION ...............................................................................................
ERRORS AND WARNINGS .................................................................................................
GENERAL TIPS FOR AN ACCURATE MEASUREMENT .............................................................
STARTUP ........................................................................................................................
RANGE SELECTION............................................................................................................
MEASUREMENT PROCEDURE ............................................................................................
VALIDATION PROCEDURE .................................................................................................
CALIBRATION PROCEDURE ...............................................................................................
GLP ................................................................................................................................
BATTERY MANAGEMENT ...................................................................................................
BATTERY REPLACEMENT ...................................................................................................
ACCESSORIES ..................................................................................................................
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TABLE OF CONTENTS
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Please examine this product carefully. Make sure that the instrument is not damaged. If any damage
occurred during shipment, please contact your local Hanna Instruments Office.
Each HI96750 Ion Selective Meter is supplied complete with:
• Sample Cuvettes and Caps (2 pcs.)
• CAL CheckTM standard cuvettes
• 9V Battery
• Scissors
• 1000 µL automatic pipette with tip
• Cloth for wiping cuvettes
• Instrument Quality Certificate
• Instruction Manual and Quick Reference Guide
• Rigid carrying case
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

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The HI96750 is an auto diagnostic portable microprocessor meter that benefits from Hanna
Instruments’ years of experience as a manufacturer of analytical instruments. It has an advanced
optical system based on a special Light Emitting Diode (LED) and a narrow band interference filter
that allows most accurate and repeatable readings. All instruments are factory calibrated and the
electronic and optical design minimizes the need of frequent calibration.
With the powerful CAL CheckTM validation function, you are able to validate good performance
of your instrument at any time. The validation procedure is extremely user friendly. Just use the
exclusive Hanna Instruments ready‑made, NIST traceable standards to verify the performance of
the instrument and recalibrate if necessary.
All instruments are splash proof and the LED and filter units are protected from dust or dirt by a
transparent cup. This makes the instruments fulfill field applications. Display messages aid the
user in routine operation. The meter has an auto‑shut off feature that will turn off the instrument
after 10 minutes of non use in measurement mode or after 1 hour if left in calibration mode.
The meter uses an exclusive positive‑locking system to ensure that the cuvette is in the same
position every time it is placed into the measurement cell. It is designed to fit a cuvette with a
larger neck making it easier to add both sample and reagents. The cuvette is made from special
optical glass to obtain best results.
The HI96750 meter measures the potassium (K) content in water samples in the 0.0 to 10.0 mg/L
(ppm) for low range and 10 to 100 mg/L (ppm) for medium range. Tetraphenylborate Method. The
reaction between potassium and reagents causes turbidity in the sample.
The reagents are in powder and liquid form and are supplied in packets and bottles respectively.
The amount of reagent is precisely dosed to ensure the maximum repeatability.
degree Celsius
degree Fahrenheit
milligrams per liter. mg/L is equivalent to ppm (parts per million)
milliliter
millivolt
Liquid Crystal Display
°C:
°F:
mg/L:
mL:
mV:
LCD:
GENERAL DESCRIPTION ABBREVIATIONS

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SPECIFICATIONS
Precision is how closely repeated measurements
agree with each other. Precision is usually
expressed as standard deviation (SD).
Accuracy is defined as the nearness of a test result
to the true value.
Although good precision suggests good accuracy,
precise results can be inaccurate. The figure
explains these definitions.
In a laboratory using a standard solution of
2.00 mg/L potassium and a representative lot
of reagent, an operator obtained with a single
instrument a standard deviation of 0.06 mg/L.
Range 0.0 to 10.0 mg/L LR
10 to 100 mg/L MR
Resolution 0.1 mg/L
Accuracy
@25 °C (77 °F)
LR: ±1.5 mg/L ±7 % of reading
MR: ±15 mg/L ±7 % of reading
Light Source Light Emitting Diode
Light Detector Silicon Photocell with narrow band interference filter @466 nm
Method Tetraphenylborate method. The reaction between potassium and the
reagents causes a turbidity in the sample.
Environment 0 to 50 °C (32 to 122 °F); max 95% RH non‑condensing
Battery Type 9V (1 pc.)
Auto‑Shut off After 10’ of non‑use in measurement mode; after 1 hour of non‑use
in calibration mode; with last reading reminder.
Dimensions 192 x 104 x 69 mm (7.6 x 4.1 x 2.7”)
Weight 320 g (11.3 oz.).
Required Reagents
Code Description Quantity/test
HI93750A‑0 Potassium Reagent 6 drops
HI93750B‑0 Powder reagent 1 packet
SPECIFICATIONS
PRECISION AND ACCURACY

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Absorption of Light is a typical phenomenon of interaction between electromagnetic radiation and
matter. When a light beam crosses a substance, some of the radiation may be absorbed by atoms,
molecules or crystal lattices.
If pure absorption occurs, the fraction of light absorbed depends both on the optical path length
through the matter and on the physical‑chemical characteristics of the substance according to the
Lambert‑Beer Law:
‑log I/Io= ελc d
or
A = ελc d
Where:
‑log I/Io = Absorbance (A)
Io = intensity of incident light beam
I = intensity of light beam after absorption
ε
λ= molar extinction coefficient at wavelength λ
c = molar concentration of the substance
d = optical path through the substance
Therefore, the concentration “c” can be calculated from the absorbance of the substance as the
other factors are known.
Photometric chemical analysis is based on the possibility to develop an absorbing compound from a
specific chemical reaction between sample and reagents. Given that the absorption of a compound
strictly depends on the wavelength of the incident light beam, a narrow spectral bandwidth should
be selected as well as a proper central wavelength to optimize measurements.
The optical system of Hanna Instruments’ HI96750 colorimeter is based on special LED and narrow‑
band interference filters to guarantee both high performance and reliable results.
HI96750 block diagram (optical layout)
PRINCIPLE OF OPERATION

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A microprocessor controlled special LED emits radiation which is first optically conditioned and
beamed to the sample contained in the cuvette. The optical path is fixed by the diameter of the
cuvette. Then the light is spectrally filtered to a narrow spectral bandwidth, to obtain a light beam
of intensity Ioor I.
The photoelectric cell collects the radiation Ithat is not absorbed by the sample and converts it
into an electric current, producing a potential in the mV range.
The microprocessor uses this potential to convert the incoming value into the desired measuring
unit and to display it on the LCD.
The measurement process is carried out in two phases: first the meter is zeroed and then the actual
measurement is performed.
The cuvette has a very important role because it is an optical element and thus requires particular
attention. It is important that both, the measurement and the calibration (zeroing) cuvettes, are
optically identical to provide the same measurement conditions. Whenever possible use the same
cuvette for both. It is necessary that the surface of the cuvette is clean and not scratched. This to avoid
measurement interference due to unwanted reflection and absorption of light. It is recommended
not to touch the cuvette walls with hands.
Furthermore, in order to maintain the same conditions during the zeroing and the measuring phases,
it is necessary to close the cuvette to prevent any contamination.
PRINCIPLE OF OPERATION

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INSTRUMENT DESCRIPTION
1) RANGE/GLP key
2) CAL CHECK key
3) ZERO/CFM key
4) READ /TIMER key
5) ON/OFF key
6) Liquid Crystal Display (LCD)
7) Cuvette alignment indicator
8) Cuvette holder
KEYPAD DESCRIPTION
• ON/OFF: to turn the meter on and off.
• ZERO/CFM: this is a bi‑functional key. Just press to zero the meter prior to measurement, or
confirm edited values. In calibration mode press to confirm factory calibration restore.
• READ /TIMER: this is a multi‑functional key. In measurement mode, press to make a
measurement, or press and hold for three seconds to start a pre‑programmed countdown prior
to measurement. In GLP mode press to view the next screen.
• CAL CHECK: this is a bi‑functional key. Just press to perform the validation of the meter, or
press and hold for three seconds to enter calibration mode.
•RANGE/GLP : this is a multi‑functional key. Press to change the parameter, press and hold
for 3 seconds to enter the GLP mode. In calibration mode press to edit the date and time.
FUNCTIONAL DESCRIPTION

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FUNCTIONAL DESCRIPTION
OPERATING MODES
• Measurement mode:default operation mode, enables both validation and measurement.
• Calibration mode: may be entered by keeping CAL CHECK pressed for three seconds
(the “CAL” tag appears), it enables calibration of the instrument.
• GLP mode: may be entered by pressing RANGE/GLP for 3 seconds (“GLP”appears), it
enables consulting of user calibration date or restore factory calibration.
DISPLAY ELEMENTS DESCRIPTION
1) The measuring scheme (lamp, cuvette, detector), appears during different phases of zero or
reading measurement
2) Error messages and warnings
3) The battery icon indicates the charge state of the battery
4) The hourglass appears when an internal check is in progress
5) Status messages
6) The chronometer appears when the reaction timer is running
7) The month, day and date icons appear when a date is displayed
8) Four digit main display
9) Measuring units
10) Four digit secondary display

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The instrument shows clear messages when erroneous condition appears. Messages are also displayed
when the obtained values are outside expected range. The beeper is playing a beep on errors.
a) on zero reading
Light High: There is too much light to perform a measurement.
Please check the preparation of the zero cuvette.
Light Low: There is not enough light to perform a measurement.
Please check the preparation of the zero cuvette.
No Light: The instrument cannot adjust the light level. Please check
that the sample does not contain any debris.
ERRORS AND WARNINGS
Inverted cuvettes: The sample and the zero cuvette are inverted.
Zero: A zero reading was not taken. Follow the instructions of the
measurement procedure for zeroing the meter.
b) on sample reading
Under range: A blinking “0.0” indicates that the sample absorbs
less light than the zero reference. Check the procedure and make
sure you use the same cuvette for reference (zero) and measurement.

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Over Range: A flashing value of the maximum concentration
indicates an over range condition. The concentration of the sample
is beyond the programmed range: dilute the sample and re‑run
the test.
c) during calibration procedure
Standard Low: The standard reading is less than expected.
Standard High: The standard reading is higher than expected.
Cap error: Appears when external light enters in the analysis cell.
Assure that the cuvette cap is present.
d) other errors and warnings
Cooling lamp: The instrument waits for the lamp to cool down.
Battery low: The battery must be replaced soon.
Dead battery: This indicates that the battery is dead and must be
replaced. Once this indication is displayed, the meter will lock up.
Change the battery and restart the meter.
ERRORS AND WARNINGS

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The instructions listed below should be carefully followed during testing to ensure best accuracy.
• Color or suspended matter in large amounts may cause interference, therefore these should be
removed by treatment with active carbon and by prior filtration.
• For a correct filling of the cuvette: the liquid in the cuvette forms a concavity on the top; the
bottom of this concavity must be at the same level of the 10 mL mark.
• Proper use of the powder reagent packet:
(a) use scissors to open the powder packet;
(b) push the edges of the packet to form a spout;
(c) pour out the content of the packet.
• It is important that the sample does not contain any debris. This would corrupt the reading.
• Each time the cuvette is used, the cap must be tightened to the same degree.
HI93750B-0
HI93750B-0
HI93750B-0
GENERAL TIPS FOR AN ACCURATE MEASUREMENT
• Proper use of dropper:
(a) to get good reproducible results, tap the dropper on the table for several times and wipe
the outside of the dropper with a cloth.
(b) always keep the dropper bottle in a vertical position while dosing the reagent.
HI93750A-0
HI93750A-0

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• Whenever the cuvette is placed into the measurement cell, it must be dry outside, and completely
free of fingerprints, oil or dirt. Wipe it thoroughly with HI731318 or a lint‑free cloth prior to
insertion.
• Shaking the cuvette can generate bubbles in the sample, causing higher readings. To obtain
accurate measurements, remove such bubbles by swirling or by gently tapping the cuvette.
• Do not let the reacted sample stand too long after reagent is added, or accuracy will be lost.
• It is possible to take multiple readings in a row, but it is recommended to take a new zero
reading for each sample and to use the same cuvette for zeroing and measurement.
• After the reading it is important to discard immediately the sample, otherwise the glass might
become permanently stained.
• All the reaction times reported in this manual are referred to 25 °C (77 °F). In general, the
reaction time should be increased for temperatures lower than 20 ºC (68 ºF), and decreased
for temperatures higher than 25 ºC (77 ºF).
• In order to maximize accuracy, prior to a measurement follow the validation procedure to be
sure that the instrument is properly calibrated. If necessary, calibrate the instrument.
Prepare the instrument for measurement as follows:
• Unpack the instrument by removing the dust protection sleeve from the instrument cuvette
holder.
• Place the battery in the instrument as described in the “BATTERY REPLACEMENT” chapter.
• Place the instrument on a flat table.
• Do not place the instrument under direct sun light.
GENERAL TIPS FOR AN ACCURATE MEASUREMENT
STARTUP

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• Press RANGE/GLP to change the range. The range can be changed any time when the
instrument is in measurement mode.
The selected range is memorized and the selection remains unchanged at power off or when the
battery is removed.
The HI96750 can measure 0.0‑10.0 mg/L Potassium when range P1 is selected and 10‑100 mg/L
Potassium when range P2 is selected.
Note: Sample dilution is required when the P2 Potassium MR is selected.
To change the range follow the procedure:
• Turn the meter on by pressing ON/OFF. The display briefly shows all tags on.
• After startup, the range identification number appears on the secondary display as P1 or P2.
Code Parameter
P1 Potassium LR
P2 Potassium MR
RANGE SELECTION

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The measurement procedure requires the instrument to be zeroed prior to sample measurement. The
instrument is “zeroed” using an unreacted sample to compensate for the sample turbidity or color.
The reagents are then added and the reacted sample is measured.
• Turn the meter on by pressing ON/OFF. The display briefly shows all tags on.
• When the beeper sounds briefly and the LCD displays dashes, the meter is ready. The blinking
“ZERO” indicates that the instrument needs to be zeroed first.
• Pay attention to the selected range. To change the range, simply press RANGE/GLP .
Note: If P2 is used a sample dilution is required (see below).
• Fill the cuvette with 10 mL of unreacted sample, up to the mark, and replace the cap.
• Add six drops of HI93750A‑0, replace the cap and swirl the solution. (Do not shake).
HI93750A-0
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• Place the cuvette into the cuvette holder and ensure that the notch on the cap is positioned
securely into the groove.
• Press ZERO/CFM and the lamp, cuvette and detector icons will appear on the display, depending
on the measurement phase.
MEASUREMENT PROCEDURE

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• After a few seconds, the display will show “-0.0-”. The meter is now zeroed and ready for
measurement.
• Remove the cuvette.
• Add the content of one packet of HI93750B‑0 powder reagent. Replace the cap and shake
gently 1 minute.
• Press and hold READ /TIMER for three seconds. The display will show the countdown prior to
measurement. The beeper will signal a tone at the end of countdown period to alert the user.
Alternatively, wait for 3 minutes.
• Invert the cuvette for 5 times, replace the cuvette into the cuvette holder and ensure that the
notch on the cap is positioned securely into the groove. Press READ /TIMER. In both cases,
the lamp, cuvette and detector icons will appear on the display, depending on the measurement
phase.
• At the end of measurement, the instrument directly displays concentration in mg/L of potassium
on the LCD.
• If the analysis result is over the method range use P2 procedure.
HI93750B-0
MEASUREMENT PROCEDURE
3" 3’
or
x5

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The following ions do not interfere below the concentrations reported: Ammonium 10 ppm, Magnesium
8000 ppm, Calcium 10000 ppm as CaCO3,Sodium 8000 ppm, Chlorine 12000 ppm.
Color or suspended matter in large amounts will cause interference. Therefore the turbidity should
be removed by prior filtration. For best results samples should be tested at room temperature
(20 OC or 68 OF). Lower temperatures will result in higher readings.
P2 Potassium MR for 10-100 mg/L
Dilute the sample 1:10 by following the procedure below
• Use the 5 mL syringe twice to measure 10 mL of sample.
• To measure exactly 10 mL of sample with the 5 mL syringe, push the plunger completely into the
syringe and insert the tip into the sample. Pull the plunger out until the lower edge of the seal
is on the 5 mL mark of the syringe. Empty contents into an empty 100 mL graduated cylinder.
Repeat this a second time for a total transfer of 10 mL sample. If available bring to 100 mL
mark with demineralized water.
Preparing demineralized water (if needed):
Note: The ion exchange resin contained in the Demineralizer Bottle is provided with an
indicator substance. The indicator will change from green to blue when the resin has been
exhausted and needs to be replaced.
Mix diluted sample:
• Pour the solution in the 170 mL beaker, replace the cap and invert several times to mix. This is
the diluted sample. Select P2 method. The procedure for the diluted sample is identical to the
P1 method. (Pour 10 mL of the diluted sample into the cuvette. Add six drops of HI93750A‑0,
swirl to mix and zero the instrument. Add one packet of HI93750B‑0 and shake gently for
1 minute. Wait for 3minutes, invert the cuvette 5 times and read the reacted sample. The final
results are automatically displayed in mg/L of Potassium. The dilution compensation is included
in the P2 method.
Note: The dilution compensation is included in the P2 software.
2'
• Remove the cap and fill the Demineralizer Bottle with tap water.
• Replace the cap and shake gently for at least 2 minutes.
• Open the upper part of the Demineralizer Bottle cap and gently squirt the demineralized water
in to the cylinder, up to the 100 mL mark.
MEASUREMENT PROCEDURE
INTERFERENCES

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• Turn the meter on by pressing ON/OFF.
• When the beeper sounds briefly and the LCD displays dashes, the meter is ready.
• Place the CAL CheckTM Standard HI96750‑11 Cuvette A into the cuvette holder and ensure that
the notch on the cap is positioned securely into the groove.
• Press ZERO/CFM and the lamp, cuvette and detector icons will appear on the display, depending
on the measurement phase.
• After a few seconds, the display will show “-0.0-”. The meter is now zeroed and ready for
validation.
• Remove the cuvette.
• Place the CAL CheckTM Standard HI96750‑11 Cuvette B into the cuvette holder and ensure that
the notch on the cap is positioned securely into the groove.
Use the validation procedure to ensure that the instrument is properly calibrated.
Warning: Do not validate the instrument with any standard solutions other than the Hanna
Instruments CAL CheckTM Standards, otherwise erroneous results will be obtained.
Note: The validation is performed only for the selected parameter. For full validation of the
instrument, the following procedure must be performed for each parameter.
VALIDATION PROCEDURE

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Note: It is possible to interrupt calibration procedure at any time by pressing CAL CHECK or
ON/OFF keys.
Warning: Do not calibrate the instrument with standard solutions other than the Hanna Instruments
CAL CheckTM Standards, otherwise erroneous results will be obtained. When calibrating, only the
selected range is affected.
• Turn the meter on by pressing ON/OFF.
• When the beeper sounds briefly and the LCD displays dashes, the meter is ready.
• Press and hold CAL CHECK for three seconds to enter calibration mode. The display will show
“CAL” during calibration procedure. The blinking “ZERO” asks for instrument zeroing.
• Press CAL CHECK and the lamp, cuvette and detector icons together with “CAL CHECK” will
appear on the display, depending on the measurement phase.
• At the end of the measurement the display will show the validation standard value.
The reading should be within specifications as reported in the CAL CheckTM Standard Certificate. If
the value is found out of the specifications, please check that the cuvettes are free of fingerprints,
oil or dirt and repeat validation. If results are still found out of specifications, then recalibrate the
instrument.
VALIDATION PROCEDURECALIBRATION PROCEDURE
3"