Thermo Fisher Scientific C101 Colorimeter - Manual (Page 50)

Calibration: pH
C401/301/101 Colorimeter
46
3.4 pH
1. Ensure at least 10 ml of clear pH7.0 buffer is available.
2. Ensure the meter is switched off. Press and hold the ZERO key while
switching the meter on by pressing the ON/OFF key. The meter will
momentarily flash the model number and then display the CAL
annunciator at the top left corner of the screen indicating the
instrument is in calibration mode.
3. For the single-parameter colorimeter (C101), the display will show
[PH]. For the multi-parameter colorimeters (C401& C301), the display
will indicate the last test performed. Press the MODE key until [PH] is
displayed.
OFF
ON
ZERO
CAL
MODE
Press Mode
to select test
parameter of
“PH”
pH calibration mode selection (Multi-Parameter Colorimeter)
4. Press the READ/ENTER key to confirm the selected test. The meter
will display [bLNK] indicating it is waiting for a
blanking sample.
Note: blanking is compulsory during calibration; without
blanking the meter will not continue with the calibration
procedure.
5. Select a clean vial, un-screw the cap and fill with de-ionised water to
the line on the vial. Replace the cap, ensuring it is screwed on finger
tight to the vial.
6. Ensure the outside of the vial is clean, dry and absent of any marks
or finger-prints. Gently push the vial fully into sample well of the
instrument, whilst aligning the ▼ mark on the vial with the ▲ mark on
the meter.
7. Press the ZERO key to blank the meter to that vial; the meter will
read [ZERo] whilst this is taking place.
8. Remove the blanking vial from the meter.
9. The meter displays 7.0 pH, with CAL annunciator on top left corner.
CAL
Blanking
Sample
CAL
ZERO
pH