Reference Electrodes

List 5 product

Ag/AgCl Electrode

    It consists of a Teflon cap with a AgCl coated Ag wire, a glass tubing, and a porous Teflon tip sealed into the glass tubing.
      Porous Teflon tip has the following advantages: slow solution leak and more durability due to its perfect chemical inertness. However, you should still take good care of the electrode. The most critical issue is that the electrode should always be dipped in KCl solutions when it is not in use. If you leave it in air by accident, the solution inside the pores will dry out causing high resistance (you will see noise increase or even potential out of control if the tip is seriously dried out). The only way to restore it is to fill it with solution and slowly push the solution through the porous Teflon tip.
    The reference electrode compartment (the glass tubing) is filled with 3.5M KCl. You can fill with other concentration KCl. The potential of the reference electrode versus the Standard Hydrogen Electrode (0.0V) can be calculated from the activity (not concentration) of Cl ion.
Before you use the reference electrode, you need to remove the cap at the end of the electrode. Tap the tubing and make sure no air bubble is trapped in the lower portion of the tubing. The electrode should be dipped into 1M KCl solution immediately and left overnight before use.
    The solution in the compartment is refillable. To do that, carefully unplug the Teflon cap by holding the glass tube with your left hand and using your right thumb to push the edge of the white cap towards the right. Do not pull on the cap and tube directly. It may cause glass tubing to break. Next, use a syringe to refill both the glass tubing and the white Teflon cap. The solution level should be full. Tap the tubing and make sure that no air bubble is trapped in the bottom of the tubing. Slowly insert the glass tubing into the Teflon cap with Ag wire. Please insert very slowly. You will see solution comes out through the tip. It is normal. If you insert too fast, it will generate too much pressure and may cause the porous Teflon tip to be popped out or damaged. After the glass tubing is all the way in the cap, let it sit for a while so that the pressure inside the tubing will be released and no solution will further leak.

Saturated Calomel Electrode

Hg2Cl2 + 2e = 2Hg + 2Cl
o = 0.241V vs NHE at 25oC for saturated calomel electrode (SCE)

Hg/HgO Reference Electrode (CS902)

Alkaline/Mercury Oxide Reference Electrode consists of Hg/HgO/1M KOH. It can be used in high alkaline electrolyte solution.
HgO + H2O + 2e = Hg + 2OH
E= 0.098V vs. NHE at 25℃
You may freely change the solution by taking off the side cover.
Electrode impedance:≤10KΩ
Potential at 25℃:0.098V
Flow rate at interface: 1drop/10min
Solution in the salt bridge: 1M KOH
1.  Please take off the rubber cover at the part of the electrode interface when use.
2. There shouldn’t be air bubbles in the solution in salt bridge otherwise the measuring circuit may be blocked. Please remove air bubbles of the tube before first use. (swing the electrode as the thinner portion towards down.)
3. During measurement, the level of solution in salt bridge should be higher than the solution of the sample.
4. Please store the electrode in alkaline solution.
5. Please regularly replace with solution in the salt bridge and clean the internal wall of the electrode.