Hi, I am trying to fabricate my own Ag/AgCl reference electrode. How can I measure the potential of it?
What is the process people usually do to check the potential and the stability of potential of it? I have a CHI1205B electrochemical analyzer. Is there anyway to do the potential check with it?
Thanks
Dip your made Ag/AgCl reference electrode and additional reference electrode of the same type (or a calomel reference electrode) in a small beaker containing 3 M NaCl. Connect both the electrodes to voltmeter.
Read the potential difference between the electrodes on the voltmeter. Ideally the difference between two electrodes of the same type would be zero. However, in actual practice there is commonly some variation. If the two electrodes are of the same type (e.g., Ag/AgCl vs. Ag/AgCl) the meter should read 0 ± 20 mV. If your reading for any pair of electrodes is significantly different, you should have another electrode of the same type handy to help distinguish which of the two is bad. When comparing an Ag/AgCl reference electrode to a calomel electrode, make the calomel the black (negative) input on the voltmeter. The meter should then read -35 ± 20 mV.
I hope this is helpful
Dip your made Ag/AgCl reference electrode and additional reference electrode of the same type (or a calomel reference electrode) in a small beaker containing 3 M NaCl. Connect both the electrodes to voltmeter.
Read the potential difference between the electrodes on the voltmeter. Ideally the difference between two electrodes of the same type would be zero. However, in actual practice there is commonly some variation. If the two electrodes are of the same type (e.g., Ag/AgCl vs. Ag/AgCl) the meter should read 0 ± 20 mV. If your reading for any pair of electrodes is significantly different, you should have another electrode of the same type handy to help distinguish which of the two is bad. When comparing an Ag/AgCl reference electrode to a calomel electrode, make the calomel the black (negative) input on the voltmeter. The meter should then read -35 ± 20 mV.
I hope this is helpful
In the response by Dr. Sardesai, there is a perfect instruction how to make the assay. I make additional information only. You can use other additional references instead of the same type as well (if you lack them or for control purposes). The difference of potential will not be zero in this case. Expected difference potentials can be learned e.g. from:
http://en.wikipedia.org/wiki/Reference_electrode
Another optional way is to measure the potential of a known redox couple for example make a 1mM solution of K3Fe(III)(CN)6 and K4Fe(II)(CN)6 and do a regular CV from the average of the catodic and anodic peaks [ (Epeak catodic+Epeak Anodic)/2 ] you obtain the standard redox potential of that species and compare it to the literature one (just remember for an Ag/AgCl electrode there is a 0.197 V for saturated or 0.2 V for 3M correction )
Both Namish and Miroslav provided the good solution for this test. Using a known standard electrode as the reference (can both be the same type or not), and then comparing the potential difference. It is better to have a high conductivity electrolyte to lower the potential loss. Repeat several times with two or more known standard electrodes to get a more accurate value.
Dip your made Ag/AgCl reference electrode in a beaker with 1 M HCl solution and take a Pt foil in to the beaker, pursue with H2 gas near to Pt foil, after saturation just measure the potential different between your made Ag/AgCl and Pt foil with multimeter (wait for some time because at starting the value was changing), that is your standard potential of Ag/AgCl. As 2 H+ + 2 e− = H2 E0(V) = 0.00
This is a very simple experiment. I hope this can help you.
The difficulties with using the hydrogen gas electrode (other than its complexity vs. using another commercial reference electrode) are that the activities of H+ and Cl- will not be unity in a 1 M HCl solution (thus the E0 of the hydrogen electrode will not be 0.00V), and if the Ag/AgCl electrode contacts the hydrogen electrode solution via a salt bridge, the liquid junction potential will be quite large. Furthermore, the hydrogen gas electrode usually uses a platinized platinum electrode, not a bare Pt foil electrode.
As you did not mention what is the concentration of the cl in your electrode.
please be aware that the potential difference between your electrode and any other standard reference electrode will depend on the concentration of Cl in your home made electrode.
Simple do Hydrogen evolution reaction with pH=0 solution, Platinum electrode both counter and working. Check the potential at which HER takes place...Note down the potiential at which HER takes place.this is the potential of your refrence electrode w.r.t SHE.
Hello,
I'm checking some Ag/AgCl electrodes against same type of electrodes I know are in very good state. I get a difference of 30 mV. Concerning the answer of Mr. Sardesai, could you please provide some reference information about "If the two electrodes are of the same type (e.g., Ag/AgCl vs. Ag/AgCl) the meter should read 0 ± 20 mV. " From which standard or guidance is this coming from? Many thanks in advance.
I don't know the source of Mr. Sardesai's value, but the difference that you observe could be due to experimental error. You talk about checking some silver chloride electrodes against others of the same type (that "are in very good state"), but you don't say how many of each, whether they are commercial electrodes and whether you get the same difference between both sets of electrodes. Without such information, it would be hard to determine the source of the difference. If I were to guess, I would say the problem may be caused by the filling solutions in the different electrodes. Unless they are all made up with solution from one source, a small difference in the chloride concentration of the filling solution could easily account for the potential difference. I would have to know more about your experimental conditions to be able to provide a more confident answer.
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