Calibrating pH and Conductivity: Horiba Meters (Older Models)

To calibrate the Horiba
conductivity meter, we want to start with turning
the meter on, removing a protective cap. And we’ll use a 1.41
calibration solution, which is 1.41 millisiemens
per centimeter or 1410 microsiemens
per centimeter. The sample well is this
little green thing. The measuring electrodes are
here in the black section. And we just want to fill the
reservoir with the calibration solution, wait for the
reading to stabilize, which is indicated with a small
happy face, which we now have. And you can see right now, we’re
reading at 1.44 millisiemens or 1440 microsiemens. We push the calibrate button. And we go into calibration mode. You can see the little symbol
there for calibration mode. And it’s calibrated
to 1.41 millisiemens. And when we get a happy
face, we’re all done. So we have a happy face. We then rinse the electrode
head with deionized or distilled water and just flush it out. Because dilution matters
for conductivity meters, we want to make sure we
always dry the sample well with a little piece of chem
wipe to get the water out, so we don’t dilute
our next reading. For the pH meter, it’s more
or less the same process, except we’re going to
calibrate to two points. Again we turn the meter on. And we open the sample well. If you prefer, you can
take this little flap off. I like to leave it on to
protect the electrode. We calibrate at pH 7 first
with the calibration solution that came with the meter. We want to put enough
solution in that we have both the
reference electrode and the measuring electrode wet
and connected by the liquid. So the measuring
electrode is here. The reference electrode
is that little white spot. And we want to have our
solution connecting both. So again when we
get a happy face. You can see that we’re at 6.99. We want to calibrate to this. So we push the calibrate button. You can see we’re
calibrating to 7.00. And we have that
little symbol showing we’re in calibration mode. Now we just wait
for the happy face. And we’ve done our
calibration to pH 7. When we’ve got our
calibration to pH 7 finished, we want to rinse
the sample well. Because we’re
measuring pH, it is not so concentration dependent. So we don’t really have to
blot the inside of the meter. If you do blot it, the glass
membrane over the measuring electrode is very sensitive. So you really want
to be very gentle, which is why I generally
don’t blot the electrode. Now we want to
calibrate at pH 4. Use the pH 4 buffer solution. Again, fill the sample well. Make sure we have both the
measuring and reference electrode dampened and we have
both in contact with liquid, the liquid is
consistently across. Again, we wait for
the happy face. We have our happy face. So we push the calibrate button. Initially it wants
to calibrate to pH 7. We don’t want that. You push again and we’re
now calibrating to pH 4. If we were calibrating to 10,
we would push one more time. And we would get the
calibration for 10. And we wait again
for the happy face. We now have our happy face. And again, we just rinse
with deionized water. And we’re all calibrated. That’s it.

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