Steps for Measuring pH Value Using an Acidimeter (pH Meter)
preparation
1. The acidity meter should be placed flat on a workbench that meets the usage environment, and the bracket should be supported according to the visual angle.
2. Positioning measurement method of pH value: (1) Two point positioning method (high-precision measurement method) (1) Connect the electrode circuit, move the reference electrode and the PH electrode that has been activated for more than 24 hours into the first standard buffer pH1 (e.g. pH1=4.00), and adjust the positioning knob until the instrument displays "0.00" after the instrument response is stable; (2) Take the electric level system out of the first standard solution, wash it with deionized water, dry the surface of the electric level with filter paper, and transfer it into the second standard solution (e.g. pH2=9.18). After the instrument response is stable, adjust the slope knob so that the acidity meter displays (△ pH=pH1- pH2=9.18-4.00=5.18). The slope knob can not be moved again after that, unless the electrode system is replaced; (3) After the slope adjustment is completed, readjust the positioning knob to display the actual pH value of the second standard solution (9.18) on the instrument, and the two-point positioning is now complete; (4) Remove the electrode from the second standard solution, rinse and absorb it, then transfer it into the test solution. The pH value of the test solution is displayed after the instrument response stabilizes. (2) One point positioning method (rough measurement method) (1) Adjust the temperature compensation knob to the solution temperature value; (2) Rotate the slope compensation knob to the left to the head; (3) Move the electrical grade system into a standard solution (using only one standard solution for the one point method, such as pH=4.00), adjust the positioning knob to display "4.00" on the instrument; (4) After removing the electric level, rinse and absorb the water, and move it to the solution to be tested. The value displayed by the instrument after the response is stable is the pH value of the solution to be tested.
Temperature measurement
1. Set the function selection to temperature mode.
2. Insert the temperature probe into the socket and place it in the environment or solution. After the instrument response stabilizes, the displayed value of the instrument is the temperature value of the environment or solution.
precautions
1. Carefully prepare the instrument before use.
2. If the acidity meter shows unstable or jumping display after being powered on or during the measurement process, the power should be cut off for inspection, such as whether the voltage, preheating time, and electrode system are normal.
3. When using different electrodes, attention should be paid to eliminating ion interference, selecting a good salt bridge, and if necessary, using an ion strength fixative.
Before transferring the electrode system from the first solution to the second solution, it must be cleaned with deionized water or double distilled water, and then dried with filter paper to avoid affecting the accuracy of the measurement results.
5. The instrument should be stored in a dry, clean, and non corrosive place. After each measurement, the power should be turned off, the electrode and temperature probe should be removed and stored properly. After cleaning, the glass electrode can be immersed in deionized water for later use (note that the water level should not be lower than the glass bulb). After cleaning, the calomel electrode should be covered with a rubber cap and stored in a matching box. When the filling solution of the calomel electrode leaks or is unsaturated or the salt bridge is interrupted, the saturated filling solution should be replenished in a timely manner.
6. This type of instrument adopts large-scale integrated circuits with high input resistance. When repairing and soldering any internal components of the instrument, a soldering iron with a good grounding wire below 45W should be used. For soldering irons without grounding wires, the power plug should be unplugged for soldering.
