Thermo Fisher Scientific C101 Colorimeter - Manual (Page 23)

Measurement: pH
C401/301/101 Colorimeter
19
2.6 pH (5.9-8.2 pH units)
• For water and wastewater (Phenol Red Method)
1. Switch the meter on by pressing the ON/OFF key.
2. For single-parameter colorimeter, the display will momentarily show
[PH] before switching directly to [STbY] as that of step 3. For multi-
parameter colorimeter, the display will indicate the last test
performed. Press the MODE key repeatedly until [PH] is displayed.
3. Press the READ/ENTER key to confirm the test parameter. The
meter will read [STbY] indicating it is in stand-by mode, waiting for
either blanking or measurement.
READ
ENTER
pH test selection (Multi-Parameter Colorimeter)
4. Select a clean and dry vial, un-screw the cap and fill with sample
water to the line on the vial. Replace the cap, ensuring it is screwed
on finger tight to the vial.
5. Ensure the outside of the vial is clean, dry and absent of any marks
or finger-prints. Gently place the vial fully into the sample well of the
instrument, whilst aligning the ▼ mark on the vial with the ▲ mark on
the meter.
6. Press the ZERO key to blank the meter to that vial; the meter will
read [ZERo] whilst this is taking place.
Note: The meter will store the last zero value it took between tests, even if it
turns off or if the batteries are removed.
Blanking
Sample
ZERO
pH
7. Remove the vial from the meter and un-screw the cap. Select a
bottle of pH Indicator (Phenol Red). Unscrew the cap and holding
the bottle vertically; gently squeeze 20 drops of the Phenol Red into
the contents of the vial. Replace the cap onto the Phenol Red bottle.
Take extra care not to over-tighten the cap.
8. Replace the cap onto the vial, ensuring it is screwed on finger tight.
Invert the vial several times to mix.