Ion selective electrodeIt is a new analytical tool for determining ion activity or concentration in a solution. According to the definition recommended by IUPAC, an ion selective electrode is an electrochemically sensitive material whose potential is linearly related to the logarithm of the given ion activity in the solution. This device is different from systems that involve redox reactions. From the definition, it can be seen that the potential of ion selective electrodes is not formed by oxidation or reduction reactions, but rather by a sensitive membrane. Therefore, ion selective electrodes are also known as membrane electrodes.
Ion selective electrodeUsage:
1) Preparation before the experiment: Equipment preparation (ion meter or pH meter, ion electrode, flask, volumetric flask pipette, etc.), solution preparation (standard solution, deionized water, electrode filling solution, ion strength regulator).
2) Electrode preparation: Add the electrode filling solution through the filling hole, ideally not higher than the filling hole. Then wait for the electrode to activate for 30 minutes.
3) Calibration: Configure 0.1, 1, 10, 100, and 1000 ppm standard solutions, and use two or more similar standard solutions for calibration. Principle: Proceed in sequence from low concentration.
4) Measurement: Immerse the electrode into the test solution, stabilize it, and read the value. If there is a certain degree of measurement error, it is necessary to comprehensively consider the influencing factors and handle it.
5) Lifespan: It is related to the properties and usage of the sample being tested. Experience value of 1 year.
Ion selective electrodeThe influencing factors
1) PH value: The existence form of different ions in a solution is affected by pH value. So when measuring, it is necessary to keep the solution within a certain pH range.
2) Impurities: There are other ions in the test solution that interfere with the measured ions. Corresponding chemical reagents need to be selected as concealment agents to eliminate interference.
3) Temperature: At different temperatures, the existence forms of various ions vary to some extent, which affects the changes in content.
Ion selective electrodeMaintenance and upkeep
1) Electrode cleaning: Rinse or soak the electrode surface with pure water. If it is not cleaned thoroughly, consider the properties of the test solution and choose the corresponding reagent. However, the rinsing or soaking time should not be too long. After using other reagents, rinse immediately with pure water.
2) Electrode polishing: For electrodes with metal film, the polishing paper provided with the electrode can be used for polishing until the electrode has a metallic color. If the effect is not good, you can use suede to apply a small amount of toothpaste to polish the metal surface of the electrode, sometimes it can have a miraculous effect.
3) Replacing the membrane head: For gas sensitive electrodes, they are often used as sensitization membranes for soft materials. If any measurement problems are found, the membrane head can be replaced and the electrolyte can be re added. Generally, electrodes come with around three of them.
4) Electrode filling solution: usually replaced every three months. There is a corresponding description in the instruction manual of the formula electrode.
5) Electrode activation: Soak the electrode in the same solution as the electrode filling solution for at least 2 hours.