Chapter 4 Calibration And Measurement; Ph Calibration And Measurement; Ph Calibration; Ph Measurement - Thermo Scientific Orion Star A111 Reference Manual

Chapter 4 Calibration and Measurement

pH Calibration and Measurement

pH Calibration

1. Press
2. Select fresh pH buffers. If calibrating more than one point (highly recommended), select pH buffers that bracket the
expected sample pH and are at least one pH unit apart.
3. Press
4. Wait for "READY" to appear.
a. With automatic buffer recognition (default, AUTO CAL appears at the top of the display): to calibrate
b. With manual calibration (MAN CAL appears at the top of the display): press
5. When finished, press
a. For one-point calibration, press
b. For two- or three-point calibration, the slope will be displayed and the meter will automatically proceed

pH Measurement

1. Prepare the pH electrode according to the electrode instructions. Press
2. Rinse the electrode (and ATC probe, if separate) with distilled water, blot dry and place into the sample.
3. If the meter is in AUTO-READ mode (meter default) press
will immediately start taking readings. Record the pH and temperature of the sample when "READY" is displayed and
"pH" stops blinking.
Note: If in AUTO-READ mode and memory storage is enabled, the reading will automatically be stored when the "AR"
appears. If in continuous read mode and memory storage is enabled, press
4. Remove the electrode (and ATC probe, if separate) from the sample, rinse with distilled water, and blot dry. To continue
taking measurements , place electrode (and ATC probe, if separate) into the next sample and repeat steps 3 and 4.
5. When finished measuring all samples, store electrode according to electrode instructions.
Thermo Scientific Orion Star A111 Benchtop and Star A121 Portable pH Meters
to display pH for pH measurement mode.
. Rinse the electrode (and ATC probe, if separate) with distilled water, blot dry and place into the buffer.
additional points, repeat steps 3 and 4a.
To calibrate additional points repeats steps 3 and 4b.
to save and end calibration.
return to measurement mode.
to measurement mode.
or to edit the slope and press the enter key to save and
. If the meter is in continuous read mode, the meter
or to set value.
to display pH for pH measurement mode.
to store into the meter's memory.
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