Chapter 4
|
Using the pH or pH/ISE Channel
ISE Calibration Procedure
Orion Star A214 pH/ISE 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.
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 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.
Thermo Scientific
Orion Star A210 Series Benchtop Meter User Manual
|
55
Summary of Contents for Orion Star A210 Series
Page 5: ......
