How to use the laboratory pH meter
Precautions before use:
(1) When using for the first time, because the electrode probe is relatively dry, it will affect the measurement accuracy of the instrument, so first soak the electrode in 3mol/L potassium chloride solution for 2 hours.
(2) Configuration of 3mol/L potassium chloride solution: Weigh 223.65g of potassium chloride and dissolve it in one liter of distilled or deionized water, and dissolve the reagent completely to obtain a 3mol/L potassium chloride solution.
(3) Replace the electrode once a year (it must be replaced regardless of whether the electrode is usable or not).
How to use
1. Preparation
(1) Turn on the power, short press the "Exit" button to turn on the pH meter to preheat.
(2) To clean the electrode, wash the electrode with distilled water for more than three times.
(3) To prepare the test solution, take an appropriate amount of the test solution in a clean test tube.
2. Calibration (the pH meter needs to be calibrated if it is not used for a long time)
Automatic calibration: Submerge the electrode below the surface of the standard buffer solution. Short press the "Calibration" button, observe the upper left corner of the display, the calibration is over when the letter Auto no longer flashes. Short press the "reading/confirmation" key to end
3. Measurement
(1) After rinsing the electrode with distilled water for more than three times, insert the electrode into the liquid to be tested prepared in advance to ensure that the electrode is below the liquid level.
(2) Short press the "Read/Confirm" button, observe the upper left corner of the display, and the measurement ends when the word Auto no longer flashes.
(3) After recording the reading, take out the electrode and rinse it with distilled water for more than three times. If you need to retest, please repeat 1, 2 operations.
4. End
After the end, rinse the electrode with distilled water for more than three times, and then insert the electrode into the protective bottle. Long press "Exit" to shut down, unplug the power, and put it back to the original place.
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5. Precautions for the use of ph meter
(1) Under normal circumstances, when the instrument is in continuous use, it needs to be calibrated once a day; generally, the instrument does not need to be calibrated within 24 hours.
(2) Before use, pull down the rubber cover on the upper end of the electrode to expose the small hole on the upper end.
(3) The calibration buffer solution generally uses a pH=6.86 solution for the first time, and a buffer solution close to the pH value of the measured solution for the second time. If the measured solution is acidic, the buffer solution should be pH=4.00; When the solution to be tested is alkaline, choose a buffer solution with pH=9.18.
(4) When measuring, the leading wire of the electrode should be kept still, otherwise it will cause unstable measurement.
(5) Do not soak the electrode in distilled water.
(6) Keep the electrode bulb moist. If it is found to be dry, it should be soaked in 3mol/L potassium chloride solution or slightly acidic solution for several hours before use to reduce the asymmetric potential of the electrode.
