Chapter
4
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pH, pH/ISE and pH/LogR Measurement Modules
ISE Calibration (pH/ISE Module Only)
One to six standards can be used for ISE (ion selective electrode) calibration. If more than one
standard is used for calibration, start with the lowest concentration standard and
work up to the
highest concentration standard last. Always use fresh standards. Select standards that bracket
the sample concentration and are one decade (10 times) apart in concentration. To accurately
prepare calibration standards from a stock solution, serial dilution is recommended using
calibrated pipettes. If ISA will be added to samples, the same ISA must be added to all
standards prior to calibration to ensure a consistent dilution factor.
Prepare the ISE according to the instructions in the electrode user manual. Connect the ISE
and any other electrodes to be used to the module inputs on the selected channel.
In
the measurement mode, press the
channel key until the channel with the pH/ISE module
with ISE connected is shown. If needed, press the
mode key until
ISE Measurement is shown
as the measurement mode and use the
ISE Mode Menu
to set the Electrode Type.
1.
Press the
f1 (Cal) key to start the calibration.
a.
If more than one channel is displayed in the measurement mode, press the
▲ or
▼
key to highlight the desired channel and press the
f3 (Select) key.
2.
Rinse the ISE and any other electrodes in use with distilled water or rinse solution required
for that electrode. Blot the electrode dry with a lint-free tissue or shake the electrode and
then place into the standard. Do not wipe or rub the sensing element of the electrode.
Follow all electrode rinsing and drying instructions or exceptions in the ISE user manual.
3.
When the electrode and standard are ready, press the
f3 (Start) key.
a.
If using
a stirrer probe, the stirrer probe will start stirring when the
f3 (Start) key is
pressed and stop stirring when the reading stabilizes.
4.
Wait for the concentration value to stabilize and perform one of the following actions:
a.
Press the
f2 (Accept) key to accept the displayed value.
or
b.
Press the
f3 (Edit) key and use the numeric keypad to enter the concentration value.
Press the
f2 (Accept) key to confirm the entered value.
5.
Press the
f2 (Next) key to proceed to the next standard and repeat steps 2 through 4 or
press the
f3 (Cal Done) key to save and end the calibration.
6.
The meter will display the calibration summary including the slope and export the data to the
calibration log. Press the
measure (esc) key to proceed to the measurement mode.
ISE Calibration Editing
Once the
f3 (Cal Done) key is pressed and the calibration is saved, press the
f2 (Cal Edit) key
to edit the calibration data and fix individual points without a full recalibration. In the calibration
edit mode, press the
▲ or
▼ key to highlight a calibration point and press the
f2 (Delete) key
to
delete the point or press the f3 (Re-Measure) key to re-measure the point. Follow the
onscreen text prompts and instructions to edit the selected calibration point.
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Orion V
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Meter User Manual
Thermo
Scientific
Chapter
4
|
pH, pH/ISE and pH/LogR Measurement Modules
Temperature
Calibration
V
ERSA
S
TAR
meters have a relative temperature accuracy of ±0.1°C. ATC probes have varying
relative accuracies, usually ±0.5°C to ±2°C. Use the temperature calibration function only
when necessary. Since the temperature offset calculated during the calibration is applied to all
future temperature measurements, recalibrate the temperature if a different ATC probe is used.
ATC Probe Temperature Calibration
ATC (Automatic Temperature Compensation) probes are defined as both separate temperature
probes and those built into electrodes. A temperature calibration can be performed for individual
ATC probes or simultaneously for all ATC probes connected to the meter. Prepare and connect
all ATC probes to be calibrated to the appropriate module inputs on the selected channels.
1.
In the measurement mode, press the
setup key.
2.
Press the ◄ or ► key to highlight Channel 1, Channel 2, Channel 3 or Channel 4 and
press the
f3 (Select) key.
3.
Press the ◄ or ►key to highlight Temperature and press the
f3 (Select) key.
4.
Press the
▲ or
▼ key to highlight Temperature Input and press the
◄ or
► key to
highlight an ATC probe (i.e. Ch2-ATC) as the temperature source for the selected channel.
5.
Press the
▲ or
▼ key to highlight Temperature Cal and press the
◄ or
► key to highlight
the individual ATC probe (i.e. Ch2-ATC) or All ATC and press the
f3 (Select) key.
6.
Place the ATC probe(s) into
a solution with a known, stable temperature. It is recommended
that two NIST-traceable thermometers be used to measure and verify the temperature.
7.
Press the
f3 (Edit) key, use the numeric keypad to enter the temperature of the solution and
press the
f2 (Accept) key to save the temperature value and update the offset.
8.
If applicable, press the
▲ or
▼ key to highlight the reference temperature of the next ATC
probe and repeat steps 6 and 7 for each ATC probe connected to the meter.
9.
Once all ATC probes are calibrated, press the
f1 (Back) key to exit the calibration.
Manual Temperature Entry
A manual temperature value can be entered when MAN is selected as the temperature input.
1.
In the measurement mode, press the
setup key.
2.
Press the ◄ or ► key to highlight Channel 1, Channel 2, Channel 3 or Channel 4 and
press the
f3 (Select) key.
3.
Press the ◄ or ►key to highlight Temperature and press the
f3 (Select) key.
4.
If needed, press the
▲ or
▼ key to highlight Temperature Input and press the
◄ or
► key
to highlight MAN.
5.
Press the
▲ or
▼ key to highlight Temperature Cal and press the
f3 (Select) key. Press
the
f3 (Clear) key, input the temperature value using the numeric keypad and then press
the
f2 (Enter) key to save the value.
Thermo Scientific
Orion V
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TAR
Meter User Manual
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