Decagon WP4-T - How to Verify and Calibrate the WP4

WP
4
PotentiaMeter
Calibration and Verification Standards
27
How to Verify and Calibrate the
WP4
Since errors in the calibration value result in errors
in all values subsequently measured, care should be
taken to do it right.
Checking Calibration
To check the calibration of your WP4, do the fol-
lowing:
1. Empty the whole vial of KCl solution into a sam-
ple cup and place it in the WP4’s sample drawer.
For best results, make sure you wait for the KCl
to come to temperature equilibrium at the sam-
ple temperature menu (Ts - Tb) before measur-
ing it.
2. Carefully slide the drawer closed, being espe-
cially careful so the solution does not splash or
spill and contaminate the chamber.
3. Turn the drawer knob to the READ position to
make a reading. Make two readings. The second
reading should be within ± 0.1 of the correct
reading of the KCl standard at that temperature.
At 20 °C this should be -2.19 MPa. At 25 °C this
should be -2.22 MPa. If you’re operating in pF
mode, it should read 4.35 pF at both 20 and 25
°C