Hey guys, welcome to the Hanna lab.
pH affects a lot of things, and its important to feel confident when measuring it.
We know everybody makes mistakes but not everybody knows when they’re making them.
Were gonna take you through some common mistakes people make when conditioning, calibrating,
and using a pH electrode and show you some best practices to prevent
these mistakes so you can feel confident in your measurements.
Remember, the best results come from the best practices.
Number Ten on the list, Using a deteriorating electrode
Just like any piece of equipment, pH electrodes need to be replaced from time to time as part
of regular maintenance.
It’s good practice to replace your electrode annually.
Number nine.
Inadequate probe submersion.
pH electrodes are built with a junction near the bottom of the glass.
When measuring a sample, that junction needs to be covered by the sample, along with the
electrode bulb.
If the junction is left uncovered, you will not only be measuring your sample, but measuring
the air around it too.
All you need to do is make sure you have enough solution to cover the junction to give you
the most accurate readings.
Number eight on the list is one that not many people notice; The electrolyte in your electrode
is not filled to the proper level.
Inside refillable pH electrodes are electrolyte solutions made for completing an electrical
circuit between the sample and electrode.
This is how you get your readings.
If the electrolyte is not filled, the electrode will not be able to obtain a stable reading.
Electrolyte solution should be filled to a half an inch below the fill hole.
Before we take a look at number seven, let’s talk about how the correct flow of electrolyte
produces faster and more accurate readings.
Refillable electrodes are equipped with a fill hole cap.
This cap serves two main purposes.
First, it is useful in keeping your electrolyte solution from leaching out of your electrode
when not in use.
Second, when you are using your electrode, you can open it to increase electrolyte flow.
Number seven on the list is not loosening the fill hole cap.
Keeping the cap tightened creates a pressure difference.
Refillable electrodes work best when the electrolyte flows through the junction.
Number six.
Choosing the wrong electrode for your application.
There are literally thousands of different types of samples.
Whether you’re measuring the pH of your soil, or dairy, or food products, you always
want to make sure you’re using the proper type of electrode.
If you’re not sure what the right electrode is for your sample, you can always reach out
to us at Sales@hannainst.com.
Our professional staff can direct you in the right direction for all your measurement needs.
We’re now at the halfway point.
pH mistake number 5, Calibration errors.
If you are worried about the condition of your electrode, you can always check the slope
and offset.
To do this, you need a meter the reads millivolts, and pH 4.01 and 7.01 buffers.
The mV reading of your pH 7.01 Buffer is your offset.
To check your slope, take the mV reading of your pH 4.01 Buffer, subtract you offset reading,
and divide by 3.
Divide that answer by 59.16 and multiply by 100.
This is your slope percentage.
If your slope is 85 – 105% and the offset ± 30mV, you’re good to go.
That brings us to number 4.
Not cleaning the electrode.
It doesn’t take long for the electrode glass to form a dirty buildup.
This build up creates a barrier between the glass and the sample, causing readings to
be inaccurate.
Cleaning with distilled water alone will not remove the coating of some organic or inorganic
materials.
What you need is Cleaning Solution.
Immerse your electrode in cleaning solution for 10 – 15 minutes before storing it away.
After you’ve cleaned your electrode, keep the electrode capped in storage solution when
not in use.
We’ve come this far, and now it’s time for our top 3 pH mistakes.
Number 3 on the list is a common mistake.
Storing your electrode in distilled water.
It is a best practice to rinse your electrode with distilled water before using your cleaning
solution and storing it in storage solution, but if you leave the electrode in pure water
for too long, it will dilute the reference electrolyte.
Diluted electrolyte causes inaccurate readings.
So like we’ve already said, when storing your electrode, be sure to use electrode storage
solution.
This will keep your electrode conditioned and working properly for much longer.
Number two is also a very common mistake.
Wiping the sensing glass.
As we’ve already discussed, electrode bulbs are made from sensitive layers of glass.
Wiping the electrode wears on these layers and creates a static charge that interferes
with the voltage reading of your electrode, giving you wrong readings.
To clean the electrode, rinse it in distilled water.
Well… we’ve come a long way to get here.
To recap, we’ve discussed Using a deteriorating electrode, Inadequate probe submersion, low
electrolyte fill levels, Not loosening the fill hole cap, choosing the wrong electrode
for your application, calibration errors, not cleaning the electrode, storing electrodes
in pure distilled water, and wiping the sensing glass.
These 9 mistakes happen to someone, somewhere, every day.
Number one is no different, and it happens more often than you might think.
Our top pH mistake, coming in at number 1, Storing electrodes dry.
Have you ever done this?
The buildup of salt on the electrode can get pretty frustrating.
And you may not even know what’s going on.
This buildup coats the sensing glass and eventually the glass becomes dry, slow to respond, and
unstable.
It takes a while to bring your electrode back to working order if it has been stored dry
for a long time, but don’t worry.
There is a way to keep your electrode working.
First rinse your electrode until it is clean.
Next, place it in storage solution for at least 2 hours.
Once you have cleaned and conditioned the electrode, make sure to calibrate, and make
sure it’s working.
If not, repeat the steps until you get your accurate readings.
So that’s it, Our top 10 pH mistakes.
If you or someone you know are doing any of these things, be sure to refer back to this
video, or our blog on these mistakes.
You can find all the solutions and equipment you need at hannainst.com
Also, don’t forget to like this video.
Find and like us on Facebook and Instagram and if you have any questions, you can reach
us with #hannaquestions.
remember, always use best practices when handling your pH electrodes.
See you soon.