Is your pH meter electrode okay? Doing so ensures accurate measurement of the electrode
H meter (also known as pH meter) is a liquid pH measuring instrument commonly used in laboratories. The electrode is an important part of the pH meter. When measuring, it is mainly to insert the electrode into the liquid and send back the data to accurately determine the pH value of the solution. Frequent cleaning, maintenance and inspection of electrodes are necessary steps to ensure accurate measurement.
So, how do you tell if a pH meter is working properly? The Souk Procurement Manager inquired about the technical information of professional pH meter manufacturers, and sorted out the following judgment methods and electrode maintenance items for you:
First judge whether the pH meter itself is working normally: insert the short-circuit plug (light head Q9 interface) attached to the instrument to the position where the pH electrode is connected to the instrument. If the instrument displays about 0-20mV at this time, it means that the potential of the pH meter is no problem. You can pull out the short-circuit plug to check whether the electrodes can work normally.
1. Prepare standard buffer solutions with pH values of 4.00, 6.89, and 9.18.
2. Install the pH meter electrode, and put the electrode into three standard buffer solutions for calibration. The corresponding potentials of the three solutions are 177±30mv, 8±30mv, and 129±30mv respectively.
3. After the calibration, clean the electrode and put it back into the standard buffer solution to measure its pH value. If the displayed pH value does not exceed ±0.02 of the standard value, it means that the electrode is normal. Otherwise, the electrode is faulty.
The service life of the pH meter electrode is closely related to the nature and temperature of the measured sample, as well as the frequency of use and maintenance of the electrode. If maintained properly, the service life of the pH meter electrode is generally 1 to 2 years. Proper maintenance will ensure that the electrodes work properly and accurately.
The maintenance precautions of the pH meter electrode are as follows:
1. The electrode should be calibrated with a standard buffer solution before each measurement, and the standard buffer solution should be the one closest to the pH value of the measured solution.
2. Avoid contacting the sensitive glass bulb of the electrode with hard objects during use, so as not to damage or scratch the glass bulb.
3. The electrode should avoid long-term immersion in distilled water, protein solution and acidic fluoride solution, and avoid contact with silicone oil.
4. If the slope of the electrode becomes lower and the response becomes slower due to long-term use, it means that the electrode needs to be cleaned. To achieve the best cleaning effect, it is necessary to select different cleaning solutions according to the types of solutions frequently measured by the electrode:
Often measure solutions containing protein, the electrode membrane can be cleaned with pepsin/hydrochloric acid lotion;
Often measure oily or organic liquids, can be cleaned with acetone or ethanol;
The electrode junction becomes dirty and black, and can be cleaned with mercaptan cleaning solution;
Soak in electrode regeneration solution for 30 seconds, and then soak in 3mol/L KCl solution for 5 hours to achieve the effect of activating the electrode membrane.
4. The leading end of the electrode must be kept dry and clean to prevent output short circuit.
5. After the measurement, the electrode should be cleaned in time, and the electrode protective sleeve should be put on. A small amount of reference supplement liquid should be placed in the bulb in the sleeve to keep the electrode bulb moist.
