Maintenance and precautions for the use of mercury/mercuric oxide electrodes (Hg/HgO)

1、 Main applications of mercury/mercury oxide electrodes

Mercury oxide electrode (Hg/HgO) can be used as a reference electrode for measuring units in devices such as acidimeters, ion meters, potentiometric titrators, and electrochemical workstations. This electrode has good potential reproducibility and is suitable for potential measurement in alkaline solutions.

2、 Main technical data

1. Internal resistance: ≤ 10K Ω

2. Standard potential at 25 ° C: 0.098V

3. Salt bridge filling solution: 1.0mol/L KOH

4. Liquid network flow rate: ≥ 1 drop/10min

3、 Usage, maintenance and precautions

1. Before using the mercury oxide electrode, please remove the rubber sleeve from the liquid contact area

2. When measuring, the Hg/HgO electrode salt bridge solution should be filled with the salt bridge to ensure that the electrode forms a circuit. The solution in the salt bridge should be higher than the liquid level of the tested sample solution to prevent the test solution from penetrating in the opposite direction and changing the concentration or composition of the salt bridge solution.

3. The salt bridge solution inside the electrode should not contain large bubbles to avoid blocking the electronic measurement circuit; If there are bubbles, you can grip the electrode tightly and shake it lightly a few times, or raise the electrode and lightly bounce it with your fingers to make the bubbles float up.

4. Not suitable for measuring media that react with mercury/mercuric oxide (Hg/HgO). If it is inevitable to use other concentrations of KOH or reactive media, it is recommended to use a double salt bridged mercury/mercury oxide (Hg/HgO) electrode to block the influence of the test solution on the core of the mercury oxide electrode.

5. Mercury oxide electrodes should be cleaned regularly and the salt bridge solution should be replaced. For general adhesion stains, they should be cleaned in a timely manner. When replacing the salt bridge solution, remove the cap from the injection port on the upper part of the electrode, extract the original salt bridge solution, and then inject the new solution.

6. Due to the presence of toxic mercury oxide in the electrode and the corrosive nature of the salt bridge solution, please strictly follow the relevant laboratory safety regulations for operation.

7. When taking the electrode cap, do not expose the electrode to air for a long time (more than a few minutes), otherwise the solution in the glass tube will leak and evaporate, which may affect the electrode performance. When the electrode is not used for a short period of time, please immerse the electrode liquid network in a 1.0mol/L KOH medium for storage. If it is not used for a long time, please replace it with a new 1.0mol/L KOH and seal it away from light for storage.

8. When taking the electrode cap, it is recommended to take both the upper and lower ends of the electrode cap at the same time to avoid causing a pressure difference between the inside and outside of the electrode and causing the flow rate of the liquid network at the lower end of the electrode to be too fast.

9. Mercury oxide electrode usage temperature: It is recommended to use it at room temperature, with a temperature of ≤ 40 ° C.

10. Reference electrodes such as mercury oxide electrodes are not suitable for ultrasonic cleaning.

11. The salt bridge solution of mercury oxide electrode is 1mol/L KOH. If other concentrations of KOH solution or other solutions are used, the electrode potential will also change due to changes in the concentration and composition of the salt bridge solution, which may also affect the service life of the electrode.