Ise Calibration Procedure - Thermo Scientific Orion Star A320 Series Manual

Thermo Scientific

ISE Calibration Procedure

Orion Star A324 pH/ISE meters and Orion Star A329 pH/ISE/conductivity/RDO/DO meters can
perform an ion concentration calibration using one to five standards with easy to follow
onscreen instructions to assist with the calibration process.
Always use fresh standards and select standards that bracket the sample concentration and are
one decade (ten 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. If more than one standard is used for calibration, start with the lowest
concentration standard and work up to the highest concentration standard last.
Prepare the ion selective electrode according to the instructions in the electrode manual.
Connect all electrodes to be used to the appropriate meter inputs. Make sure the meter
measurement mode is set to ISE.
1. Press the f1 (cal) key to start the calibration.
2. Rinse the ion selective electrode and any other electrodes in use with distilled water, blot
gently with a lint-free tissue to remove excess water and place into the standard.
3. When the electrode and standard are ready, press the f3 (start) key.
4. Wait for the value on the meter to stabilize and perform one of the following actions:
a. Press the f2 (accept) key to accept the displayed concentration value.
or
b. Press the f3 (edit) key to access the popup number entry screen and manually enter
the concentration value.
i. Press the p, q, t or u key to highlight a number or decimal point, press the
f3 (enter) key to select the highlighted item and repeat until the desired value is
shown at the top of the screen.
ii. Press the f2 (done) key to save the value and exit the number entry screen.
iii. Press the f2 (accept) key to accept the manually 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. If five standards are used, the
calibration will save and end once the fifth value is accepted.
a. When performing a one point calibration, press the f2 (accept) key to accept the
displayed slope value or press the f3 (edit) key, use the popup number entry screen to
enter a new slope value, press the f2 (done) key and then press the f2 (accept) key.
6. The meter will display the calibration summary including the slope and export the data to the
calibration log. Press the f1 (meas) key to proceed to the measurement mode or press the
f2 (print) key to export the calibration data to a printer or computer.
Chapter 4 Using the pH or pH/ISE Channel
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Orion Star A320 Series Portable Meter User Manual 61
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