calibrate Acidimeter It is formed by an electrode. Because the electrodes are variable in response, the electrode and pH meter must be standardized to compensate for electrode changes. The more repetitions you do, the more accurate your measurements will be. Daily or higher standardization will provide more accurate results.
Success or failure glass electrode PH measuring device Properly covered, it will withstand a great deal of adverse conditions and maintenance. The pH electrode is a very thin glass membrane that breaks easily. At Measurement, glass electrodes are normally maintained in an acidic solution with a pH = 3. When you do not use the electrode, the tip of the probe must be kept moist, otherwise the pH sensor membrane will be electrodes due to lack of moisture, causing the electrode to malfunction. Rinse and dry the electrode with water. Then place it in the buffer solution with pH = 1.07 and make sure that its branch (located below or next to the electrode) is wet. Store the electrode in KCl solution or electrode storage solution.
Electrode Calibration
Before measuring the pH, you need to calibrate the electrode. To do this, you need at least two solutions with a known pH. In this case, buffers with pH // 4, 7 and 10 are often used. Details of the calibration process depend on the model ph meter You have. The first step is usually in relation to temperature correction. Some models automatically measure temperature. Others do this with the help of an external probe. Sometimes you have to enter the temperature obtained by other measuring devices on the panel of the device using the available buttons. The next step is to place the electrode in the buffer solution with = 7ph. The electrode must detect the pH correctly. Next, remove the electrode, rinse with distilled water and wipe with a dry cloth. Then immerse in another buffer solution whose pH has already been determined. Wait for the displayed number to be fixed. This may take up to a minute. Modern pH meters often automatically detect the buffer and perform the required function. On older models you have to press one of the calibration buttons to ph meter Display the number 7.
Note: Sometimes the pH is read fluctuatingly. If the fluctuations are small, use the calibration button to find the right position so that the number 7 for the zero position of the device appears on the screen. Larger oscillations may be caused by improper connection of the device or electrode cables. Therefore, in case of encountering them, checking the connection lines is a priority. The next steps depend on the solution you want. If you want to measure the pH of an acidic solution, use buffers with a pH of 4.01. If you are testing solutions with higher pH, use buffers with = 10ph. Keep in mind that high pH buffers tend to absorb 2 CO, so perform the calibration immediately after the test tube is filled with the buffer solution.
How to use
For proper use, it is necessary to go through the steps of working with the device properly. for this purpose:
- Acidimeter Turn on.
- Rinse the electrode with distilled water and dry it with a paper towel (do not rub it dry).
- Immerse the electrode in buffer solution with 7PH =.
- Press the Calibration button.
- Wait for the PH icon to stop flashing. Press the calibration button again.
- Rinse the electrode with distilled water and pat dry with a paper towel.
- Dip the electrode in a paste with a pH = 10. When it comes to standardizing a new one, clean the existing buffer. Use the setup and enter buttons to clear the existing buffers.
- Wait for the icon to stop flashing, then press the measure button.
- Rinse the electrode with distilled water and wipe dry.
- Dip the electrode into the sample.
- Press the measure button.
- Wait for the PH icon to stop flashing, then record the PH of the sample.
The pH of the device is assumed to be 07.01 by default. If this number is not correct, adjust it with the up and down arrows on the device. When the changes stop and the displayed number remains fixed, the device screen prompts the user to press the OK button. This process takes time if the electrode is dirty. After this step, the device asks the user to put it in another buffer with a pH of usually 1.04. This value can be changed depending on the application. Rinse the electrode and place it in the selected buffer. After the device also accepts the secondary value, press the OK button. You can repeat these steps if needed for other buffers.
Possible errors
1- If Accepted two buffers, will show Good Electrode.
2. If the phrase “wrong buffer” appears on the screen, use a new electrode, or clean the previous electrode and use it again.
3- If the phrase “wrong electrode” is displayed, it means that the electrode is not connected well.
If the electrode is dirty or clogged with oil, etc., the measuring device will display a result that is not correct. Cleaning solutions are available to eliminate this problem. Measuring instruments have also been introduced to the market that can display the age of the electrode and its deposition rate.
Test the electrode in millivolts
with the help of the MODE button of the device, select the mv mode. Then place the electrode in buffers with pH = 4 or pH = 10 as mentioned. If the mv displayed for each buffer is in accordance with the table below, the electrode operation is correct.
