Sample requirements – Hach-Lange PHC745 User Manual
Page 5
•
The calibration and sample measurement conditions must be as similar as possible
(e.g., the temperature of the solution, the stir procedure, the stir rate and the position
of the probe).
•
If a calibration error occurs, refer to
on page 13.
Calibration procedure:
1. Connect the probe
to the meter. Make
sure that the cable
locking nut is correctly
connected to the
meter. Set the meter
to on.
2. Push Calibrate.
The display shows the
buffers that are
necessary for
calibration.
3. Prepare the fresh
buffers in separate
beakers or applicable
containers.
4. Rinse the probe
with deionized water.
Dry with a no-lint
cloth.
5. Open the sleeve
junction. Put the
probe in the pH buffer
solution and stir
lightly. Make sure to
fully put the reference
junction into the
standard.
6. Push Read. Wait
until the reading
stabilizes.
7. Do steps 4–6
again to collect the
minimum number of
calibration points
specified in the
calibration options.
8. Push Done to view
the calibration
summary.
Note: The display will
not show "Done" until
the minimum number
of calibration points is
collected.
9. Push Store to
accept the calibration
and go back to the
measurement mode.
Sample requirements
N O T I C E
Some probes are not compatible with specific sample types. Probe damage can occur.
•
Samples must be aqueous. The probe can also make measurements in partially
aqueous or some water-miscible solvents. Read the results with caution because the
full pH scale changes when the solvent system changes.
•
Probes with a Red-Rod reference system are compatible with solutions that contain
silver complexing or binding agents (e.g., TRIS, proteins and sulfides), as they have
an encapsulated reference system.
•
Proteins can collect on the sensing element. Make sure that the probe stays clean
when these types of samples are measured.
•
Do not use the probe in solutions that are out of the temperature range of the probe.
Refer to
•
For low ionic strength (LIS) or high purity samples, use an LIS chamber or a flow cell
to prevent sample contamination.
5